I would say go whenever works for you. It could happen, but if September works better book that. We are planning last week of August next year. We've been going to the Outer banks for 13 years the end of August/beginning of September, and have had to cancel twice because of hurricanes. Yes it does happen, but that's the timeframe/prices that work best for us, so that is when we plan (and why we are planning Disney). We are just aware that we could have to cancel.
The thing about hurricanes and vacations from our experience is they usually only impact a couple days (I'm just talking vacations here, not taking light of the situation and the people that could be impacted personally with loss of life/property/etc). Like this one, if you were leaving Disney by Saturday AM or coming in Tuesday, there are most likely less issues to arise. We've had close calls with hurricanes that have been within a few days, and a week or two of our vacations, but everything gets back to normal in the Outer Banks relatively quickly. However, if your trip is to begin those days or they are in the middle, it changes the entire vacation.