Any sufficiently advanced extraterrestrial intelligence is only indistinguishable from God to those who do not know God to begin with.
I sometimes toy with the idea of writing a SF story of the turmoil that would happen if an alien civilation was at last discovered, and their religion exactly matched one specific religion found on earth, esentialy proving it to be true. Can you imagine what the scientific community would do to surpress that, and the chaos when the info got out, the reaction of other religions etc.?
Sadly (or perhaps not) I just don't have the time.
Especially if it turned out to be coconut tree worshipers in the South Pacific.