Actually, the official opening time is usually 9 am. You can usually enter the parks at around 8:30, but you will be held at the Port of Entry (IOA) or in the Hollywood area (USF) until around 9. Sometimes you may be let in anywhere from 15 to 5 minutes before 9 if everything is ready. Between 8:30 and 9, you can get breakfast, sundries, film, go to the bathroom, etc.