Exiting Germany after registration

I move to Germany at the end of this month and have a date to register for my residence on the 15th of September.

How long does it take to get a resident permit processed so I can leave an come back?

I plan on flying to my home country on the 29th of November, I am booking a flight that’s non-refundable (it’s the cheapest) but before I do it, I want to have a safe window.

Help!

Edit: My student Visa is a multi entry visa

Edit 2: I realised that I actually have an appointment to register my address and not one for a permit :/ so now looking to a permit appointment but I am guessing I can travel though since my visa is multi-entry