I don't know about this.
While the Pope's generic statements in the article regarding 'martians' are gracious, the other statements made by the Vatican's chief astronomer, José Gabriel Funes, seem to me to be a little bit at odds with the basic theology of the Bible. He says that maybe E.T.'s theology would be "more advanced" than ours, and perhaps we'd find that we'd want to convert to it. In what way could E.T.'s theology be more "advanced" than ours, and why would we want to convert it? If their theology is some kind of cosmic extension that ties itself nicely into the Bible's theology without going all LDS about it all, maybe so. But if it ends up being some kind of completely alternative religion, one that precludes or excludes the identity and need for Christ, I'd say we have a problem on our hands--one not much different than Christians already have while living in a world with multiple religions. Same story, different planet.
Personally, I like the general approach J.J. Davis (2002) has in contemplating how our Christian theology could deal with the possibility of Extraterrestrials by adapting some insinuations of Colossians 1:15-20:
I believe that the Christology of Colossians is sufficiently vast in scope to provide a basis for the redemption of fallen beings anywhere in the universe, without the need for any additional incarnations or atonements. (p. 152)
Maybe this is a similar angle to the one from which the Pope made his comments about ET's?
While this would solve some of the theological issues for Christians here on planet earth, another problem might arise if E.T. thinks he's morally ok and not in any need of any kind of Savior (which, by the way, doesn't sound so "alien.")
REFERENCE
Davis, J. J. (2002). The Frontiers of Science & Faith: Examining Questions from the Big Bang to the End of the Universe. InterVarsity Press.
2PhiloVoid