You'll probably be okay in September, as long as you're not too particular. I've been doing some poking around just to get an idea of what availability is like across the resorts at different times of the year, and right now September is pretty much wide open everywhere, for almost all room types. If you want a studio at VGF or one of the very popular booking categories at a couple of the other resorts, you might be out of luck. Otherwise you'll likely have lots of options.
thanks for that info. We are going for a long weekend for our 30th anniversary.