A person who exclusively deepthroats penises of 9-or-more inches in length. Gender and age varies, but most tend to be obese males between the ages of 12 and 40.
PERSON 1: Hey man, do you think I could get a date Todd?
PERSON 2: Doubt it. He's a 9gagger.
Derived from 9gag, defined as "a horrible excuse for a website than sic mainly incorporates stolen materials and ideas from other legitimate websites. 9GAG is also a large source of child pornography."
A 9gagger is someone who creates and/or promotes and/or enjoys such websites. Colloquial usage refers to anyone who is slimy, dishonest, disgusting, or a pedophile.
This egregiously gross website might appeal to creeps, pedophiles and 9gaggers, but never to normal people.