Re: Which Catamaran should I choose?
I agree that 9 people sounds like a lot. I charted a Moorings 4600 last year with ten berths that would have worked well (no sleeping in the salon required).
Besides four doubles, there's a nice little forward berth that is fun for a younger one. (The 10th is a crew berth, not as suitable.)
I wouldn't worry about performance issues. After sailing monohulls for years my experiences with charter cats have been very pleasant. You're going with a big family to enjoy the water and sun. Comfort will be more important than performance. My two cents.