Re: 9.9 and 15hp Honda outboard starter
Don't know about Honda, most other 9.9 & 15 brands share same engine block, just carb, timing, cam, reed valves, whatever method detuned versions. Grab a parts manual, check on line both codes. The 15 HP must have a dented flywheel in order to swap the 9.9 electric starter motor, if not, probably must do a flywheel swap too.
Happy Boating