Can a 9 year old be gay?

A better question would be, "Can you know you are gay at age 9?" The answer to both are apparently yes. When we look at gayness as an identity or a broader social construct, it is possible to believe you are gay at age 9 and identify as gay. So keep in mind that having sex is not required to feel or identify as gay.

It is possible that people are born either Straight, Gay, Bisexual or Asexual, so it that case, it is possible for a person of any age to be gay whether or not they know it yet.