There was a sci-fi novel where the MC had a low level gene rank, and was experimented (?) on this crazy scientist (?). Afterwards, he accepted this request/job as a space mercenary (?) and worked on a space ship. The job was to act as this relatively high-ranking military person's (fake?) son at one of the schools. I remember that in the school he chased a car (?) with a skateboard (?) (both were flying). While acting as the son he also because the student of some famous professor (?). Lastly, he got acted out a assassination as the 'son' which finished to job... I think that was it.