Looks like steel so you could try taking the cage off the body and putting it in a bench vise to bend it back. But these things are so common and inexpensive that it might not be worth your time. I would just grab a used one on ebay or from a member here. A new Shimano Acera or Shimano Sora derailleur will prob work just fine. The Sora might require a narrower 9-speed chain.
.
