Different people have different gods, and somebody worship alien gods. Thus, I should say that aliens are not my gods.
Just as we can trace back where a particular word came from, or where a specific kind of carved stone originated, we can also trace where the first references to particular god came from. The idea that, in questions like this, no ultimate truth can be reached represents what I call Facebook logic. And yes, from a religious perspective people are always free to believe as they choose.