The average resort Signature meal takes between 1.5 and 2 hours. So, if you have an 8:55 pm reservation, my guess is you'll be either eating your entree (if you started with an appetizer) or just finishing up with the entree when it's time to head out to view fireworks. Just let you server know you want to watch fireworks and they'll try to help you time the meal so the you're between courses when the show starts.
(To clarify, the reservation time is fine if you want to eating at CA Grill during fireworks. It's too late if you were hoping to request a window table with a view of the fireworks. By then, all of the window tables with a view will likely be taken and those folks are unlikely to leave until after the show. The general advice is to make a reservation for at least 2.5 hours before the show starts if you want to have a chance at a window table with a view.)