When USF opens one hour earlier than IOA

We have 3 day universal park-to-park tickets. Our first day will be Monday Oct. 12. We do not have early entry. We thought we would spend the whole day at IOA which opens at 9:00. If USF opens at 8:00 that day, is there any reason why we shouldn’t run over to USF and get one or two rides in and come over to IOA on the Hogwarts express, or should we just wait in line for IOA so as not to potentially mess up our touring plan for that day?

Express normally starts in IOA so I would just go direct to IOA.