As pointed out by u/CosmeticInk5, that's because of the All-Arounder perk, which means that the Bod counts not only as a shotgun, but as an assault rifle, sniper, pistol, and SMG. They rightfully ...
Kickballer can be farmed by defeating a specific boss, just like most other legendaries in Borderlands 4, so it's pretty easy to get. You can start farming for Kickballer quite early in the game, too.