Most kids do not get pubic hair at 9 years old but it's normal for some 9 year old boys or 9 year old girls to have pubic hair.
Puberty for some kids can begin earlier than normal in both girls and boys.
For girls puberty can begin as early as age 8 but usually not until age 10 to 12.
For boys puberty usually begins around age 10 to 12 but everyone is different and it's normal for a boy or girl to go through puberty much sooner and grow pubic hair.
Just like a girl can grow breasts sooner than another girl.
There's really no set age that a kid goes through puberty but there's an average age which is around 10 to 12 for most kids.