Started new pack of birth control yesterday 11am, left pack at home today and wont be able to take pill until 9pm. do i need to use backup protection?

Delay with BCP's: This delay may provide slight breakthrough bleeding, but if you continue taking the active pills on time, you will still be protected this cycle. If the bleeding continues, stop the pack , wait five days, and start another pack at the selected best time (at the same hour each day of active pills).

You'r probably safe: A 10 hour delay in taking your active contraceptive pills may (but is very unlikely to) cause any problem in pregnancy protection or bleeding. It would be fine to simply continue taking your pills; try to take them as regularly as you can. The use of "backup protection" is always a good idea. Be safe