Is my 8 month old behind?

He just turned 8 months old but he only says mama dada and possibly hi? Lol mostly just says dada all day. He hasn’t crawled on his hands and kness just army crawls everywhere he can pull himself up on stuff and stand but my other son was walking at 9 months... ive been so busy with two maybe im not doing enough for him? I feel terrible about it after scrolling through here seeing where other babies are at. Also he has tons of food allergies so were also super behind in the solids. I feel like im doing everything but maybe im not good enough? I do definitely hold him a lot because he gets into everything and with a 3 year okd who leaves stuff everywhere and running around i feel like my 8 month old doesn’t have the freedom my other som had as an only child. Anyone else have this problem?