and dont accept anything before 7:30. our first trip, we had a 7:10 PS and when we requested an outside table at the podium, we were told they dont start seating the "illuminations tables" until 7:30.
If Illuminations is being shown at 9pm, I would recommend a 7:30pm seating. Make sure when you make your PS you indicate you would like a patio table. I would then check in early in the afternoon to confirm this request and then once more when you check-in to be seated. Better safe than sorry.