There are many different fronts in all levels of football. In each defensive front, coaches and players need a way to communicate different alignments when setting up against an offense. To do that, we use a numbering system that tells us where each defensive player is aligned in comparison to an offensive lineman. If a defensive lineman is directly in front of an offensive lineman, they are an even number. If the defensive player isn’t directly over the offensive player, they are an odd number. There are some nuances, based on whether the the player has an inside shade or not. If they do, an “i” denotes that.
A 9-technique aligns outside of the tight end. Any defender aligning in that area is considered a 9-tech regardless of whether a tight end is present or not. A 9-technique is also called a wide-9.
9-techniques are pass rush specialists. They aren’t expected to contribute as much in the run game. Since they align so far outside the tackle, they need true speed to be able to get to the quarterback in time. They force offensive tackles to get out of their stances faster and put them in space where they can work pass rush moves on the perimeter.