Herbicides, dig a trench and insert a barrier, or keep them cut down. Mine have spread in a circle. I have a Yunan that shot out a runner about 6 feet which was unusual from my other bananas.

Herbicides - what to use? Won't this kill the entire clump?
Barrier - what to use? Where to find it?
Keep them cut down - if a sprout/pup starts to emerge and I cut it off at the ground, that pup will die or quit growing and the rest will be unharmed?

Herbicide - RoundUP or Killzsall brands. It should only kill what is sprayed.
Barrier - they make a barrier for bamboo. You can find it on the web if you use keyword " Bamboo barrier ". Dig a trench and place a barrier of plastic, concrete, etc that will not rot or crack and allow a root to penetrate.
My uncle has a large patch of mature bamboo that has reached its limits with the size he desires and he just steps on the sprouts as he finds them and keeps it contained.

Other option, if you can, is just dig them up and separate them. Free plants !

Yank them out. When a pup is a foot or two high, get a firm grasp on the base with dry hands and give it a good, sharp yank. It will pop right off at the base. I've contained my clump for years this way.