Did you just start allowing him to feed himself? He may not have gotten the hang of it. Give him something he likes to eat, and let him hold it and maybe help him bring his hand to his mouth. Don’t worry he’ll get the hang of it soon.
My baby is 8 mths old too. I already start giving him biscuits around 6 mths old. Let baby hold the biscuit but you guide with your hand to put it into his mouth. Keep doing it until baby knows how to eat on his own
I read somewhere that you could also demonstrate to him as well… let him watch u eat, show him how you eat your biscuits or food and let him learn to put things into his mouth