This is a pretty wild but fun topic :-)
Saint Augustine discussed a colorful rumour from his time about dog-headed people (cynocephaly). If you look beyond the actual rumour itself, his thinking provides a useful precedent for contemporary Christians to frame discussions about alien intelligence.
(If I remember correctly...) Augustine's thinking went something like this: if dog-headed people exist, then the question becomes whether they are descendants of Adam or not. (See the protoevangelium in Gn 3:15; or the genealogy in Lk 3:38; or the Catechism paragraph 402 and surrounding paragraphs on the Fall.)
If they are, then they are in need of salvation: the Gospel should be proclaimed to them and presumably they should also receive the Sacraments.
If they are not, given that Adam is our actual ancestor, then we might need additional revelation, because no revelation about this was provided to begin with (Jn 10:16 is taken to be a reference to non-Jewish peoples, who are also descendants of Adam and who would also end up worshiping the God of Israel by the sacrifice of the Cross, as predicted in the Old Testament).
I'd say this need for extra revelation would become even more pressing in the case of supposed intelligent life that is extra-terrestrial and, despite its rationality, fundamentally does not share in human nature and the Fall. My intuition (as a Catholic) is therefore that we will never encounter extra-terrestrial intelligence. Or if its existence is proven, then we would only learn about it from distant observations, e.g. through the SETI program, but we would never have meaningful interactions with it/them.
So far, actual evidence lines up with this more skeptical attitude inspired by the Christian faith: consider the Fermi paradox; or the vast size of the universe and our current understanding of challenges related to faster-than-light travel; or the questionable nature of the existing reports, together with very pragmatic but pressing questions like "why on earth would such advanced aliens secretly buzz around on Earth in highly advanced aircraft and still crash"...
The interesting twist (...imho...) is this: "extra terrestrial intelligence", aside from scientific debates about e.g. likelihood and discovery, also serves a cultural purpose. It is one way in which today's non-Christian society tries to think about what "it" might become. This is not unlike how thinking about angels provides Christians with a view of what they may become individually in relation to free will, moral choices and God, things which in angels are completely pure because they are immaterial creatures. The irony is that the reality of extra-terrestrial intelligence is completely unproven and its nature is therefore a matter of pure speculation and fantasy; whereas immaterial spirits actually do exist and we have some knowledge about them, expressed in solid metaphysical concepts.