The iRobot Roomba S9 is a premium robot vacuum in the manufacturer's high-end S Series lineup. It performs quite well across a wide variety of surfaces, is very well-built, and maneuvers effectively on a wide range of surfaces. It also has outstanding battery life, allowing it to clean fairly large spaces without running out of charge. Unfortunately, it has quite a few parts that require regular maintenance or replacement. Still, if you're looking for a robot vacuum that can cope with a broad mix of different floor types, it's a good choice.
The iRobot Roomba S9 is very good on bare floors. It clears pet hair and small debris such as rice without an issue, though it does experience a slight drop-off in performance with a full dirt compartment. It feels quite premium and has a long battery life that allows it to clean big rooms without running out of charge. Unfortunately, it has a lot of parts that need to be serviced regularly and has relatively high recurring costs.
The iRobot Roomba S9 is good on low-pile carpet. It clears pet hair and coarse material like sand very easily, but it may take a couple of extra passes to clear finer debris, like baking soda. It's also well-built and has a very long battery life, which helps when cleaning big spaces. That said, it has quite a few recurring costs and can be a little finicky to maintain.
The iRobot Roomba S9 performs decently on high-pile carpet. It maneuvers effectively even on densely-woven carpet and does a good job of clearing various kinds of debris on this surface, though it struggles somewhat with messes like baking soda spills. However, it can be quite pricey to maintain and has quite a few parts that you need to maintain regularly.
The iRobot Roomba S9 is an excellent choice for pet owners. It does a superb job of sucking up pet hair on a wide mix of surface types and feels quite well built. While the vacuum has quite a few parts that need to be serviced or replaced, you can remove its brushroll to detangle hair wraps. It also has a HEPA filter to trap allergens as you clean.
The iRobot Roomba S9 is a robot vacuum that isn't suited for cleaning stairs.
The iRobot Roomba S9 is a robot vacuum that isn't designed to clean the inside of cars.
The iRobot S9 is very well-built. Its D-shaped body, similar in profile to that of the Neato Botvac D7, is made of high-grade plastic, accented with a matte-finish copper lid. Its dirt compartment feels mostly sturdy, though its bottom does feel somewhat flimsy and could potentially break if it's dropped. It comes out of the box ready to use, with no assembly required except for setting up its dock station.
This vacuum is quite demanding in terms of maintenance, with quite a few parts that need to be serviced regularly. Thankfully, they're quite easy to access.
Any part that's washed in water should dry for 24 hours before use again.
This vacuum has quite a few sources of recurring costs that can add up over time.
If you don't want to buy these parts individually, the manufacturer sells a 'Replenishment Kit' that includes three side brushes, multi-floor rubber brushrolls, and three HEPA filters.
This vacuum has outstanding storage capabilities. It's quite small and comes with a low-profile charging station with a nook to store any excess length of power cable.
This vacuum has an okay dirt compartment. It's fairly sturdy, though its bottom feels like it could potentially break if dropped. It features sensors to let you know once it's full, either via an in-app notification or with the indicator light on top of the vacuum turning from white to solid red.
This vacuum's range is limited only by remaining battery life, though it can't climb up or down staircases.
The iRobot S9's portability is mediocre. It's a little heavy and lacks a carrying handle to help you carry it from room to room or up and down flights of stairs.
The iRobot Roomba S9 has remarkable battery performance. It automatically adjusts to different surface types, though you can manually adjust its power setting through three levels: 'Lower', 'Balanced', which is the default, and 'Exceptional'. Even in its strongest suction mode, it supplies just under 50 minutes of continuous runtime. Used more conservatively, its continuous battery life extends to over two and a half hours, which is fantastic. The LED light on top of its body notifies you of the current charge status, with the light going from white to red when its battery level is low.
This robot vacuum has a couple of different quality of life features. It features a dirt sensor to detect high concentrations of debris and focus its power in those areas. It also has three power levels and an auto-adjusting vacuum head to suit different floor types.
The iRobot S9 comes with two multi-floor rubber brushrolls. Unlike the more common three-armed side brush used by other vacuums in the manufacturer's lineup such as the iRobot Roomba i7+, it comes with a five-armed side brush.
The iRobot S9 is a robot vacuum with no alternative configurations.
The iRobot S9's performance on bare floors is excellent. It clears pet hair and small debris like rice without an issue, with no noticeable drop in suction power as the dirt compartment fills up. While it sucks up larger debris quite easily with an empty dirt compartment, it struggles more when the dirt compartment is filled.
The iRobot S9 is great on low-pile carpet. It clears pet hair without an issue and doesn't have too much trouble dealing with coarse material, such as sand. However, it may take a couple of extra passes to fully clear finer debris on this kind of surface, like baking soda spills.
The iRobot S9 delivers good performance on high-pile carpet. It picks up pet hair easily and clears quite a bit of coarse and fine debris on its first go-around, though it may take a couple of extra passes to clean up everything.
This robot vacuum has amazing maneuverability. Like the iRobot Roomba i7+, it uses the iAdapt 3.0 navigation system to create an efficient cleaning route and maneuver around obstructions. It also goes over spots that it deems in need of additional cleaning. The vacuum itself isn't very tall, so it shouldn't get stuck under tables or couches. While it can get stuck on rug tassels, it doesn't get tangled on obstructions like power cables, though it may push them around.
The iRobot Roomba S9's automation features are passable. During setup with the iRobot Home companion app, it uses its navigation system to create a virtual map of the layout of your home. This allows you to schedule cleaning times for individual rooms and set up virtual boundary markers. The app also shows your previous cleaning history and remaining battery life. One convenience is that if the vacuum runs out of battery while cleaning a room, it will remember the incomplete job and return once it's been recharged.
You can purchase a charging station/dirt bin separately or as part of a more expensive S9 variant, called the S9 Plus, which gives the vacuum a standalone dirt compartment built into its charging dock to automatically empty itself of debris and continue cleaning.
Another variant of the iRobot Roomba S9, referred to as the iRobot Roomba S9+, comes with an external dirt bin/charging station for automatic debris disposal. It's also currently the only other vacuum in iRobot's S Series model range. We can't confirm that this model performs similarly, as its automatic dirt emptying capabilities could have an impact on performance. We tested the base variant with no external dirt compartment, and you can see its label here.
If someone comes across a differently-equipped iRobot S9, let us know in the discussions below so that we can update our review.
The iRobot Roomba S9 is a versatile robot vacuum. It cleans effectively on a wide mix of surfaces, feels quite sturdy, and offers exceptional battery performance. it also comes with a HEPA filter to trap allergens as it cleans. Unfortunately, it also has quite a few recurring costs and can be a little tricky to maintain, with quite a few parts that require regular servicing. If you're looking for alternatives, take a look at our list of recommendations of the best robot vacuums, the best robot vacuums for pet hair, and the best robot vacuums for carpet.
The Roborock S6 and iRobot Roomba S9 are somewhat evenly-matched, but for different reasons. The Roborock is slightly easier to maintain, incurs marginally lower recurring costs, has a longer overall battery life, and is more effective with clearing large debris, like cereal, on bare floors. It also has a mop attachment to deal with wet messes, but we don't test that particular feature. Conversely, the iRobot performs better on carpeted surfaces, has a slightly larger dirt compartment, and charges almost twice as fast.
The Neato Botvac D7 and the iRobot Roomba S9 have different strengths. The Neato is much easier to maintain, has a considerably longer minimum battery life, and performs better on bare floors. The Roomba feels better-built, clears more debris on both low and high-pile carpet, and can maneuver around obstructions like electrical cords more easily.
The iRobot Roomba S9 is a better overall robot vacuum than the Roborock S5. The Roomba is better-built, charges faster, and performs much better on carpeted floors. That said, the Roborock is easier to maintain, has lower recurring costs as well as longer minimum battery life, and performs slightly better on bare floors. It also features a remote piloting app in its companion app.
The iRobot Roomba S9 is better overall than the iRobot Roomba i7+. The S9 performs better on all surface types, feels better-built, has lower recurring costs, and has a maximum battery life more than twice as long as the i7+. The i7+ does come with an automatic dirt disposal feature. This effectively gives it a much larger dirt compartment via an external dirt bin that it can return to when full. However, it should be noted that the same option is available for the S9 at an added cost.