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Highly unlikely. And moreover, such an idea is still confronted with the same problem of life emerging from non-life on Earth. And finally, as with all other aspects of nature, the extremophiles are best explained by biblical creation:

http://www.answersingenesis.org/articles/am/v4/n1/discontinuity

The Extremophiles found at the surface weren't even noticed until fairly recent times. But I'm talking about the ones deep within the earth who are living in perfectly acceptable micro-environments that can, over geologic time, be quite compatible with life of that type.

Again, they were only noted recently.

Not having been mentioned in the Bible I believe the traditional religious response has been to write them off to a "separate creation".

Now, regarding "separate creation" what you want to look for are the Church Father's arguments regarding "state of grace". They are quite relevant to the issue at hand. BTW, you have to remember that for about 90% of its history the Catholic Church was pretty much subject to the Creationist Theory, so "separate creation" was a solution regularly proposed to deal with anomalies in that particular theory. Appeals to "modern Church positions" will not help us illuminate this particular debate. My understanding is the "separate creation" and "state of grace" standards for outerspace critters haven't been updated, just abandoned for the time being.