Eh, religions have to dispel a dozen graver epistemic threats than that before breakfast every morning. If and when evidence of extraterrestrial life is found, religious people will adapt their beliefs to accommodate it and retcon it, just like they always have.
It's what they've done, very successfully, ever since they had to stop burning heretics at the stake.
>adapt their beliefs to accommodate it and retcon it
I believe this is called “learning” in common nomenclature. They do the same thing in science very regularly, and it’s a pretty obvious part of discovering the world around you.