True the 204 Ruger has more energy, but how much of that energy is going to be transferred to target? For varminting at long ranges you use up a good bit getting there.
At 100 yards the 204 is way ahead of the 9mm, especially when you factor in adjusting for drop, but inside even 20 yards how much of that energy is just going out the back of the target? I am guessing a lot no matter what bullet is used.
With the 9mm almost all of it can be delivered to target with good ammo.