If it is a 9:00 opening day, arrive early enough to mosey down Main Street, and really enjoy taking some awesome pictures.
It really is magical to have it mostly to yourself!
I would say at least by 8:00 arrive at the gate. It is unlikely you will be seated early. It seems as though we have had our longest ADR waits at CP for some reason!
It usually takes us an hour to hour and 15 min. for character meals.
Have a great time!