For most Christians, it’s not difficult that God is a Creator of life, period. This allows for the idea that there is life on other planets.
However, the problem is that the sin problem does not allow for visitations from these life forms, because of the contamination that they would cause. I do believe that we are a quarantined planet until the time comes when God will judge men and the angels. The sin issue will be settled at that point and then we will be free to wander the universe and stay on other worlds. :)
Only if these beings are sinless would it be possible. Or did Jesus die for the sins of other creations over and over. That is the sticking point for me.