My baby's weight is 7.4kg from march until now... no change at all, but he is so active & moves around so much.. he's turning 9 months in 2 days.. Should I be worried?

So long as baby is active, no weight or minimum weight increase is fine unless baby not feeding well. Alternatively, you may wish to chk with the nurses or doctors on this especially if baby is going for the milestone assessment. Personally i feel that this is not too big an issue.