I think that would bring up too many logical inconsistencies with what the Bible says.
(1) All humans are sinners (hence all need salvation--including alien humans).
(2) Jesus died once (precludes Jesus incarnating as an alien human on another planet and being sacrificed again)for all (all would include alien humans if they existed).
(3) The Bible states that salvation is though Jesus alone.
(4) God desires all be saved.
Jesus' sacrifice took place on Earth, and the good news of the gospel of salvation is only known on Earth. So any alien humans on another planet would have not access to the gospel and no way to be saved through Christ--which clearly conflicts with point #4 above.
The idea that you could have an entire planet full of humans (or multiple planets for that matter) that had no chance of salvation seems to conflict too much with what the Bible says about salvation to make it a possibility.
The Bible deals ONLY with our earth; and, prescribes nothing related to this question. For Pete's Sake, the Bible was originally directed at people who didn't even know what stars were or that the sun was a star and the earth orbited it. How could the Bible address something like that. Just buecause it didn't address that stuff is no reason to believe non-Biblical stuff doesn't exist or is by default evil.