Engaging in procreational intercourse with 9 other individuals (could be male or female, depending on what makes that good ol' wood stand up straight). The person "doing 9" has to insert his penis in all 9 members or have a penis inserted inside him by all 9 members.
An expression used to simply indicate one's desire to manage their life in any manner which they prefer. It can be applied to various scenarios in which the individual places an emphasis on his choice to take any course of action which he pleases.
- Yo, do you still talk with that girl you used to go out with?