My 9 month wont eat with spoon,wont sit up,not teething, Global development delay ? ,can you please help ?

My son seems a bit lazy with everything,all he does is eat pretty much everything ,doesnt play with toys only chew them ,he doesnt eat with the spoon much ,hasnt started teething and wont sit up yet ,I m fearing a global development delay ,What should i do to encourage him to do what he s meant to do at his age