Welcome to the forum
Decent enough choice, if you can find a 15hp I'd say better to have a bit more power in case you had a tide to work against.
The 3.8 will take up to a 25hp engine, you might find with a 9.9hp and 1-2 adults + 1-2 kids you will take a while to get on plane or not at all, if plane not required then it will push boat along fine. The Honwave comes up with some good reviews, well built and holds value, other Chinese built types also have similar reviews.
Lots of info and opinions on here for sib choice, lots of love for the Bombard Aerotec - more pronounced V keel - but the HW is a lot of boat for the buck. A 3.8 was one of the sibs to go to last year's Scottish Sib outing and seemed to cope well with conditions
Get some photos up once you get going or ask for advice if you need