Traditionally this is a very low crowd time. Many people will take their kids out of school for WDW, but lots of them don't want to do it that early in the school year.
In order to get the crowds up at that time, Disney started the free food deal several years ago. Still, crowds will be pretty light. Just be sure to get ADRs because everyone who goes then will be on the food plan so the popular restaurants will be booked up.
The main problems then will be heat and humidity. It is prime hurricane season too, but I wouldn't worry about that at all, they give lots of warning before they come and Orlando is not on the coast anyway. The buildings at WDW are very strong too, they are fine if a storm hits.