8 months old unable to sit

My 8 months old boy is still unable to sit, he is able to sit a while less than 10 mins with our support but after a while he will gets rowdy and keep leaning back or to the side. Distracted him with toys but he can only focus for a short while. Don't like to eat solid too :( any idea what's happening or what I can do to help him to sit independently? Thank you in advance!