iRobot Roomba S9: Specs, Features, Pros & Cons
Dust lines along baseboards are the complaint the Roomba S9 was designed around. Its answer is a body shaped like a D, with a flat front that lets the brush run up to the join, and an extending arm that sweeps what the flat front misses out of the corner.
Everything else about the S9 belongs to the camera-guided side of iRobot's range. vSLAM navigation builds the map, divides the floor into rooms and keeps out of no-go zones, and it works best when the lights are on. Zone cleaning runs from the same map. Carpet detection, recharge-and-resume, dual rubber brushes against tangling, and app and voice control are all present, with the usual voice assistants on the list. The body is fairly low.
Filtration is a strength with a running cost. The S9 has a HEPA filter, which few robots in the category carry, but the filter cannot be washed, so it goes on the shopping list with the other spares.
Some jobs the S9 does not do at all. It vacuums only, and anyone who wants mopping needs a second robot or a mop and bucket. Its listing shows no self-emptying dock, where the newer j9+ has one along with a lower body. And the camera navigation makes it a daytime robot, since a schedule set for the small hours asks it to find its way in the dark.
What remains is a robot for a home where the corners bother someone more than the mopping does, and the robot runs while the house is light. Among Roombas, it is the one whose shape is part of the cleaning.
Category strengths
Where the iRobot Roomba S9 beats the median
- Has HEPA filter ?
- A slightly more compact design ?88.9 mm vs 96.8 mm (median)
Where the iRobot Roomba S9 trails the median
- No a mop function ?
- No washable filter ?
How this VS Score was computed
Score 46: each known spec is measured against the median of all robot vacuums (58 products), then weighted; 50 means level with that median. In classes of six or more, a value beyond the class’s 10th–90th percentile range counts as that limit, so one extreme product cannot set the scale. 19% of the scoreable weight could be used; unknown values, features not applicable to this class and proxies (battery capacity where a rated life exists) add or remove nothing.
| Specification | This product | Cohort median | Score weight | Points moved |
|---|---|---|---|---|
| Mopping | No | 79% of the class have it | 0.6 | −28.8 |
| Edge-cleaning extension | Yes | 79% of the class have it | 0.4 | +20.0 |
| HEPA filter | Yes | 29% of the class have it | 0.4 | +20.0 |
| Navigation | Camera (vSLAM) | LiDAR | 1 | −17.0 |
| Washable filter | No | 88% of the class have it | 0.2 | −9.6 |
| Height | 88.9 | 96.8 | 0.5 | +2.0 |
Not scored: Suction power (unknown: not scored); Mop lift (unknown: not scored); Carpet detection (standard for the class (98% have it)); Cleaning modes (unknown: not scored); Max cleaning area (unknown: not scored); Mapping (standard for the class (98% have it)); Multi-floor maps (unknown: not scored); Obstacle avoidance (standard for the class (100% have it)); No-go zones (standard for the class (100% have it)); Threshold clearance (unknown: not scored); Battery capacity (unknown: not scored); Runtime (unknown: not scored); Recharge & resume (standard for the class (95% have it)); Self-empty dock (unknown: not scored); Auto-refill mop (unknown: not scored); Mop self-cleaning (unknown: not scored); Automatic mop removal (unknown: not scored); Mop wash temperature (unknown: not scored); Warm-air drying temperature (unknown: not scored); Automatic detergent dispenser (unknown: not scored); Dirt detection & re-mop (unknown: not scored); Dustbin capacity (unknown: not scored); Water tank (unknown: not scored); Noise level (unknown: not scored); App control (standard for the class (100% have it)).
Editor’s note
The S9 is the D-shaped Roomba, and everything interesting about it follows from that shape.
A round robot cannot reach all the way into a corner (the geometry does not allow it), which is why a room cleaned by one keeps a faint outline of dust in the angles. The S9's flat front lets the brush run right up to the join, and it adds an extending edge-cleaning arm to sweep debris out of the corner and into the path. If baseboards and corners are what bother you about robot vacuums, this is the design that addresses it directly.
The rest is capable and a little dated. Navigation is camera-based vSLAM with mapping, no-go zones and room-by-room cleaning. It works well in daylight and less well in the dark than the LiDAR machines here. There is a HEPA filter, dual rubber anti-tangle brushes, carpet detection and recharge-and-resume, with 120 minutes from a 3,300 mAh battery.
Two things to weigh. The filter is not washable, so it is a consumable. And it does not mop, and at 89 mm tall it will be stopped by low furniture that an 80 mm machine clears.
Buy it if corners and edges are the specific thing you want solved and you clean during the day. Night-time runs call for a LiDAR machine, and mopping for a Combo model.
Specifications
Quality bars show where each figure sits between the lowest and highest of the 58 robot vacuums this VS Score is measured against.
Cleaning
Navigation
Battery & dock
Design
Smart features
Maintenance & filtration
Sources and verification
Where the specifications come from
- Datasheet or manualhomesupport.irobot.com
- Independent testingrtings.com
Verification
- First published
- Specifications last checked
- Sheet completeness
- 17 of 39 specifications verified; the rest show as Unknown and are never estimated or scored
- Page type
- Product specification page — Compiled from the manufacturer’s published specifications and the cited sources; this is not a hands-on test.
- Basis
- Research-based: specifications and editorial text were compiled from the documents listed here and the manufacturer’s published data. We have not tested this unit ourselves; where independent measurements are mentioned they belong to the linked publication.
Robot Vacuums with similar specs to the iRobot Roomba S9
Ratings & reviews
No reviews yet. Be the first to share your experience.
The bottom line
The iRobot Roomba S9 earns a VS Score of 46 on the 19% of specifications we could compare like for like — an indication, not a ranking.
- Who it’s for
- Anyone whose complaint about robot vacuums is dust left in corners and along baseboards, with cleans run in daylight.
- Who should look elsewhere
- Night-time schedules and anyone who wants a filter that can be rinsed rather than replaced should look elsewhere.
- The trade-off that matters
- Vacuuming only. The D-shape solves the corners, and the floors still need a separate mop or a second machine.
- The main alternative
- iRobot Roomba j9+: a newer camera-guided Roomba with a self-emptying dock and a lower body
The VS Score is calculated from the weighted specifications above, each measured against the median of comparable robot vacuums — a shortlisting guide, not a substitute for your own priorities. See how we score.
