Keep your derailleur in line.
The very first aluminum frames didn't have replaceable dropouts. So, you could bend them back a few times, but then the hanger would snap off and it would be off to the bike shop for a new frame. Thankfully, those days are over. Your Niner frame comes with a replaceable dropout that can be removed if it's bent and replaced with a Niner Replacement Derailleur Hanger.
The Replacement Hanger bolts directly to the frame–it's easy. just make sure you choose the right one. One fits the EMD, Air 9, and Jet 9. Another fits the WFO v.2 12x142mm TA and RIP 9. A third option fits the Air 9 Carbon and Jet 9 RDO. The Other fits the Sir 9 and MCR.
Niner Replacement Derailleur Hangers are made of aluminum and come in black.