Unlikely by Disney bus, but an outside chance. You could try it and just get there late.
With your own car it is doable.
By cab yes but cabs will be in demand.
In all cases, the key is to get out of Fantasmic! before it ends or at least at the very front of the exit surge. We hate to be herded in that crowd so as the show is nearing its end we duck low and run up the steps to the top... turn and see Mickey say "Some imagination, huh!?" then FAST WALK to the exit.
Then you are at the mercy of the bus timing, or finding a waiting cab, or tram timing to get to your car, and car lot jam to get out.