That depends on your baby's own unique feed requirements. Is he/she eating solid foods? How much? Is her weight and growth within projected chart for his/her age? All this affect how much he/she would need. Some baby eats more and some less but all within a certain standards.. Assuming all normal 9 mth baby with 2 solids meal and 2-4 snacks a day, I'd say he/she would need 6oz per milk feed 3-4 times a day