We've gone in September a lot, but the first two weeks, not the last. The first two weeks are always very quiet, so I assume the rest of the month is also quiet. It's just the two of us also, and never get PS's. We don't like to be tied down to be somewhere at a certain time. But, we have never had a problem getting a seat at any restaurant. When it's just two, and there are fewer crowds, finding sufficient seating at places to eat is not a problem. We've never done a water park (Stephen does not like them) but, weather wise, I don't see it as a problem. It's as hot as August. We've had pretty good luck the last two years on weather. Little rain and no tropical storm. A tropical storm hit just prior to our arrival in September 01, but it was gone by the time we got there. You could see the aftermath, but that's all. Have a good time, September is the best kept secret we know.