An internet meme, similar to "I'm 12 years old and what is this".
It originally started on the website mylifeisaverage.com when a poster said that their 9 year old daughter read the website and that the other users of the site should watch what they said.

It is used as a joke when something inappropriate or something using cuss words is posted.
Person 1:Omg, I'm so badass.
Person 2: My 9 year old daughter reads this!
by quinchles October 6, 2009
its simple he likes little kids and won't stop until he finds them all
Kyle likes 9 year old its just that simple
by 9 year old predator December 17, 2018
You have kids like azeem,yousef,yusuf who snap themselves vaping as if anyone cares. You have clapped teachers like mr ahmed who say there taking you on a trip to Barcelona.
Year 9 moseley kids are the most weird kids ive met
by Wagwarn123 May 23, 2021
The 9 year old can usually be found in their natural habitat: either Fortnite or Gacha life.

9 year olds are really wild and sacred animals who are prone to yelling at deafeningly high pitches which are about 69420 hz. They have a really weird language that consists of fortnite, gacha life, roblox, etc. And they always yell swear words at each other, even including racist and homophobic slurs, as well as using gay as an insult. They will never shut up about hanging the filthy sluts. Oh and, if you don't have the most modern shit ever, they will slaughter you at a chicken slaughterhouse and sell your remains as Robux.
9 year old Timmy begged mommy and daddy to get him Fortnite, but he already had Fortnite. Because it wasn't the most modern shit ever, he killed the putrid cunt f_____s with his MEGA HYPER GALACTIC FORTNITE GUN 666. And he deafened his parents just yesterday. I worry for the quiet kid who has to sit next to him.
by bananabrainnnnn August 2, 2022