I'm assuming your arriving after October 3rd in which case, there's plenty time for them to open breakfast. I wouldn't worry this early in the game.
90 days hits October 13 but breakfast is not open yet. This statement is a good sign. Thanks for sharing.This is now at the bottom of the Be Our Guest page (color added is mine):
So those of us waiting for late October and November have to wait a while. We're still more than 100 days out.
Reserve Your Table Now
Lunch and dinner reservations can be made up to 180 days in advance, and are strongly recommended for all meals, especially dinner. Breakfast reservations can be made up to 90 days in advance.
The reservations which extended the original July 15th deadline (I think that was the date) were not released until mid to late June. Following that logic, I would expect not to see these release until mid to late September. They are probably doing them in blocks to see which months fill up (summer months versus back to school months) before they determine if this will be a permanent meal at the restaurant.
But, as with Disney you never know. They may very well open before September but I wouldn't count on it. All we can do is keep watching and be sure to post if something opens up so others can know.