I just got a 7 month old 9 lb ragdoll kitten.
From this article, a 9 lb kitten should eat about 500 kcal/day:How Much To Feed a Kitten: Kitten Food Portions and Feeding Schedule
But Royal Canin Kitten Chaton suggests to eat 3/4 cups each day for a 8.7-11 lb kitten, where 1 cup has 369 kcal, so...