My Bella was 8.6 lbs from 12 to 24 mos....I just took her in for her check up and shots last month and she is 9.6 lbs now

and she is 29 mos now...Vet told me she feels good not over weight, she did alot of filling out this past year.
your baby is only 10 mos he is still a baby and not done growing yet, he will probably put on a few more lbs...I bet he will be a good 5 lbs by the time he is 2 years old and full grown.