Eh, you've got it all backwards. You cannot get a job at X by going into the ordinary Google hiring pipeline, and in any case the Google hiring system does not hire people for specific products like Google Play Store. Furthermore, one does not freely transfer between X and Google, in either direction.
Actually, they are part of the normal Google pipeline (or at least they were before the Alphabet split). A few years ago, I was contacted by a recruiter from Google and after talking to her I ended up being interviewed by someone for a job at Google X.
