Re: 9.9 conversion to 15
Probably, but it won't make your 9.9 a 15. Also, there were some changes on the 15 hp carbs around 1994 so it may be that much different still.
If you want a 15 hp I'd recommend you sell your 9.9 and buy a 15 hp. It will be cost prohibitive to try to convert yours. The carb thing is a myth. It was only true for a few years in the 1970's (1974-76 or 77).