Right size is better
I had a 9.9 on our 26', and it was strong enough in all conditions. For a 22, I would say a 9.9 is as big as I would go or overkill. A 15 HP is too much (though yes, likely the same weight as the 9.9).Certainly it will work, but I would much prefer a smaller engine. It will be lighter, for better balance, faster sailing

, and easier to use. My wife used to have trouble lifting and maneuvering the 9.9 (4-stroke honda).So, if I already had the engine, I'd probably use it, but if buying it, look for the right one for the boat.