What are you trying to order? I could be wrong, but I think everything that Apple is selling now is available to order today.
Edit - I stand corrected. I looked at Apple's site and the Ultra says Check Availability 9/23 if you want an in store pickup. I'd start looking like I was voting in Chicago - Early & Often.
You might want to reach out to your local Apple Store(s) to see if they'll tell you how many they're expecting. Years ago I tried that for a launch day iPhone and some stores wouldn't provide that info and some would.
Depending on how badly you want it, you might want to consider standing in line before 10. Someone walking into an Apple Store might get it before your order goes through.