I don't think that the bible specifically refers to aliens (apart from angelic beings) or to other planets, but it does often refer to there being many heavens and I think I vaguely remember a reference to God as a lord of many worlds as well. There s nothing specifically saying that he did not create life elsewhere, but also no indication that he did or that we should concern ourselves about such matters. Christianity makes no predictions about whether their is alien life, so its discovery would not really prove or disprove anything (although what we learn from the aliens could be taken as evidence for or against it I guess, depending on what that is).
I believe that I've read that the Koran specifically states that God made many different inhabited worlds, so the existence of alien life may very well strengthen the Islamic faith. As Islam is supposed to be preached not only to men but also to djinni (who were not made in God's image but do have free will to serve him or rebel), there would probably be a great effort to convert any sentient species encountered.