It is not necessary to get into the creation/evolution debate to answer this question about SF plots. Creationists also believe that Earth is the homeworld of mankind, and that we’ve been here longer than 3,000 years. And old-earth creationists while they might make whatever arguments about things they perceive as missing in evolution, don’t deny that life on Earth has been here a very long time, and primate life for many millions of years, and that it arose here.

DNA shows us we are all related, all the life forms on this planet. Most people think this is because of common ancestry, though some think it’s because of a common divine designer — but either way humanity is not from any planet other than this one.