Puppy advise

Hi there! I have a 9 month old English bully and need some advice. When should I switch him to adult food? He weighs about 30 pounds and gets one cup of Blue Buffalo puppy food 3x a day. I am starting to be curious if it’s not enough. He gets hangry and chewy before meal time. He also has been teething a lot still on furniture and my arms and ankles. How can I help him get out of this??