We had a 5:30 flight to Disney last weekend, and it was delayed 3 hours The kids were so bummed about that.
I'd consider getting to the hotel early on the 8th anyway if the weather is nice. You can take advantage of the resort pool and spend the day relaxing there. There are beaches not too far, but I don't know that they're amazing enough to want to do an hours drive to and from just to see them. If you want something cheap, the Orlando Science Center is fun and is free with any ASTC reciprocal memberships.
Also, we tried the Park Fare dinner for the first time on our trip last week. I have two boys, and they had a ton of fun. The characters were great with the kids.