After studying for 15 months, Patrick Kluivert has received his certification to be professional football trainer. He received his certificate after the game between Young PSV vs Young Allemania Aachen. The all-time topscorer of the Dutch national team is not planning to immediately start as a head coach, but prefers to start as an assistant to an experienced coach.

So i guess we can conclude he has retired from playing football.

It seems so. Though he doesn't explicitly say anything about his future, the original Dutch article implies a role as an assistant trainer will be his next career step. I think he'd have mentioned it if he wanted to return as a player before that.