It is about a 30-minute show, and since buses run for at least an hour after the official park closing, you are going to be just fine to catch a bus home to your resort.

Yes, Disney World bus transportation continues to operate well after the final performance of Fantasmic! at Disney’s Hollywood Studios. Disney typically provides bus service for at least 60 to 90 minutes after the park officially closes, or until the park is clear of guests. Because Fantasmic! often ends right at or slightly after the official park closing time, a large surge of guests heads toward the exit simultaneously. To accommodate this, Disney maintains a steady fleet of buses at the Hollywood Studios terminal to transport guests back to their respective Disney Resort hotels. If there are multiple showings of Fantasmic!, buses continue running until the second crowd has exited. While the lines for buses can look intimidating immediately following the show, they usually move quickly as Disney prioritizes clearing the park. For guests staying at resorts accessible by the Disney Skyliner or Friendship Boats, those services also typically run for a similar duration after the park's closing.