No. Scientologists believe people are spiritual beings, not their bodies, and that they move on to another body once they die. Some believe they have been around for a long, long time. Some believe that this universe is a massive infinite space and that there is life on other planets. So it could be said that some Scientologists believe in “aliens”, meaning life on other planets.
Now, I have never seen any writings about (or Scientologists talking about) a belief that an alien lives inside them or that there is a spaceship buried somewhere waiting to take all Scientologists away.
There is no worshipping of aliens found in Scientology scriptures. Nor does such worshipping take place informally.
There are some people spreading the utterly false idea that Scientology is based on alien beliefs or ancient aliens or something of that nature. Scientology is based on communication, knowledge and understanding and provides help to master life and gain more understanding about it.
There are a lot of twisted interpretations of Scientology religious beliefs on the internet. I am happy you came here to find out more! Contrary to rumors and biased media reports this is not Scientology’s “Creation Theory”. The purpose of these bigots is to ridicule Scientologists, trying to make fun Scientology’s true religious beliefs. Well, if they have to invent stories to ridicule Scientology then the true Scientology seems to be worth to look at. You can do that at the Scientology Video Channel, for example.
I think the whole alien thing comes from the next question.