WARNING: To those who believe that they will become gods... with their very own planet to control!
God is a jealous God.
Just noting that it is more likely that life from Earth seeded other worlds in the solar system. Like the Martian meteorite, meteorites crashed off the Earth have made it to Mars or Titan or wherever.
There is also a class of bacteria, the smallest ones known, that can withstand 1,000s of times the radiation that any other living organism can withstand. The bacteria survives and slowly repairs its DNA. Scientists say that the radiation level they can withstand would never have existed on Earth so there would be no need to evolve this ability. That ability, however, would come in handy on a rock in deep space.