As of 2015, the average weight for a 9-year-old is 62 to 63 pounds, according to Disabled World. Weight can vary for each person, due to height and genetic factors.
To consider a person healthy, the body mass index ratio needs to be 18.5 to 24.9, states the National Institutes of Health. For a child to be overweight, this ratio ranges from 25 to 29.9. An obese person has a body mass index over 30, and a person with an index below 18.5 is underweight.
Children and teenagers have growth spurts that can cause rapid weight gain and loss, so Disabled World does not recommend dieting for young people.