A well-deserved lashing(physical or verbal) issued to a female.
This is not to be confused with wife-beating, spousal abuse or unwarranted attack. A "title 9" occurs when the actions of a violent or disrespectful female are reciprocated with the same reactions a violent or disrespectful man would have received.
Jerry: "Hey Steve, what the heck happened to your girlfriend's eye? She looks like she got dominated!"
Steve: "Oh yeah, she slapped me the other night during an argument so I issued her a title IX. She's not getting any sympathy from anyone(despite her best efforts) so I think she learned her lesson...."