Quick thoughts/questions:
1. Hourly employee scheduling guidelines vary, depending on the state that you live in. In the state that I live in, an employee can be scheduled for an unlimited number of hours per day, but cannot be scheduled 7 days in a row if working retail. In other words, you CAN be made to work a 10 or 12 hour shift without receiving any overtime pay, and without your employer violating any laws or state workforce commission guidelines. You have to have worked 40 hours during a seven day work week to begin qualifiying for overtime pay.
2. We are still not clear on whether the OP is being compensated for his time spent in the store past 8:30pm. OP, are you getting paid $9.25/HR between the hours of 8:30pm-10:15pm, or are you getting paid $0/HR?
3. We are also unclear as to whether the OP is being asked to clock out, or stop recording his time worked after the bike shop closes at 8:30pm. OP, does your manager tell you to clock out at 8:30pm, or do you clock out at the same time that he does when leaving the store at 10:15pm? How do you record your work hours...do you use a timecard, or do you log into/out of scheduling software?
4. It is entirely possible that the OP is getting paid for his time and doesn't realize it. OP, how many hours are recorded on your last pay stub, and how do those hours match up to the amount of time you actually spent in the store working during that pay period?
If you can answer the above questions, we can give you better advice.