"I normally take my birth control pill at 11pm and today i want to change the time from 11pm to 9:30pm. Would me the time stop it from working?"

Changing it to a bit earlier is fine. The concern comes from taking it later than usual. Try to keep it consistent with the new time.

It will be fine,

Also a change, even late, does not "stop it from working" it just lowers the effectiveness.

May I suggest that you refrain from intercourse for a day or two before and after the time change. That should keep you in the clear.