There is no scientific proof to support creationism, whether it be from a god or an alien life form. There is lots of proof, on the contrary, to support evolutionary development from a big bang or similar occurrence in history. There is also plenty of support to back up the evolution of each species.
The idea that aliens created human life is simply a conspiracy theory. Humans evolved alongside the rest of the life on the planet over billions of years. If aliens had created human life, then it is unlikely they would have just left the planet. There would be concrete, undeniable proof and evidence of their visits.
Although I believe there may be aliens that exist on some far away planet in the universe, I do not believe that humans were created by aliens. I think there would be more conclusive evidence that aliens existed if humans were created by aliens. Also, the aliens that created humans would be monitoring earth, and I believe humans would have detected this activity by now.