We went during a very slow week in November, but this place is popular for the chance to see Illum. However, just an FYI: totally different experience is possible there...about 1/3 of the seats are in a side room with NO view at all (and there are "window seats" in there, too...but the view looks at the walk-way going towards China...no view of the lagoon at all, so no Illuminations view.) We checked in at 7:40 and requested a window table...we were thrilled when they said "sure, no problem"...then we were seated at the window in the side room . Whoop tee doo, what a thrill. We expressed our dismay at this table: the hostess said it could take an hour or more to get a table in the other room...basically they'd put us on the bottom of the walk-up list--IF they were still taking walk-ups, which she wasn't sure about. When seated at 7:45 the hostess told us they basically seat the last tables in the main room at about 7:30 and those people all tend to stay until Illuminations is over. We've seen Illum. many times so we kept that table . The food & service was good.
Anyway, when Illum. starts, they dim the lights in La Hacienda (to the point you cannot see your plate to eat, even in the room with no view) If you're seated in the side room, you are allowed to get up and stand in the back of the other room where you have a so-so view (you're at the back of the room)
At 8:15, I'd say you have very little chance of getting a table with any view.