So sorry to hear that...Just an FYI, I know you probably don't want to hear this now, but you did not actually have to wait for the park hours to be published -- the Fantasmic dates were loaded in for September long before the September calendar was published on the website. Next time you're trying to do this & the calendar's not out, call on the earliest day you can & ask for Fantasmic package for next available day after your arrival date.
Anyway, if you're set on seeing Fantasmic while you're there, please believe all the talk about getting there EARLY - the old "you can get there 20-30 minutes before the show & still get a seat" is no longer true at all. Buy a to-go meal or bring some snacks with you & be in there 60-90 minutes before the show. Relax and enjoy a chance to sit & visit.