Turning 9 mos, suddenly my baby hates baby chair, car seat, and his bouncer. Once I put him in, he becomes hysterical. What happen and what should I do?

maybe ur baby just felt panic bcs on babychair,car seat and bouncer felt like no freedom.If ur baby dont like dont push them there.

It was happened with my baby too. He started love to explore around the house and new environment.

Maybe he has been placed in there for too often. Try going for walks

I suggest trying other activities. He may just be bored.