That depends on if they believe in original sin, not many people still do. I think only very fundamentalistic sects would have major problem with accepting the existence of extraterrestrials.
It doesn't matter if they accept original sin or not, angels and other extraterrestrials are mentioned all throughout the Bible.
Also the consequences of original sin were constrained to the earth and the flesh which was made from the "dust of the earth"
Gen 3:17 And unto Adam he said,Because thou hast hearkened unto the voice of thy wife, and hast eaten of the tree,of which I commanded thee, saying,Thou shalt not eat of it: cursed is the ground for thy sake; in sorrow shalt thou eat of it all the days of thy life;
Only "the ground" was cursed, not the ground of any other planet.
