@Alexis ill try to call tomorrow. I'm starting to think that something is wrong and that's why he's doing it
My baby girl does this all the time and she’s 9 months as well. Pediatrician says it’s normal. She does it on walls, floors, crib, etc. I would still consult a pediatrician but mine said it’s just a way of self-soothing or self-stimulating. I’ve noticed my girl does it a lot when she’s beginning to get tired.
My girl does not do that at all, only bangs her head by accident sometimes. I would maybe call a pediatrician