So many ways to go with this. FPS sells air guns, and most humans buy them from wally world and not PA, or Arizona.
Second, while yes that 1400fps with alloy pellets will not hit paper at 10 yards, put a nice heavy pellet in there, slow that sucker down to the upper 900's and it shoots very nice and very accurate. Something most Gamo bashers don't understand. They are actually good guns, most say made in Spain on them, unlike half of your cork sniffing brands that come from china.
If you want to scare away a critter get a red rider. Here the deer are so tame, I could hit them in the side with a thrown ice cube and they still would just wonder out of ice cube range. Red Rider I can arc that pellet quite a distance....and even if you never hit it, the sound of it hitting the ground will generally spook them.
Generally once you get to 9mm they are not pellets any longer they are bullets. So there is that.
No 22 air rifle will come close to 22lr in power....not yet anyway, and if it does you run into that problem with pellets not being shaped to give good accurate results once you start getting them up to super sonic levels. And I think we are a ways off from an air gun tossing a 40grain pellet as sub sonic levels. It will happen sure, but not for a while....and who knows what the culture will be at that time.
As to the kitty, personally I hate cats....but I would be knocking on your neighbors door, unless you are not controlling your animal and it is pooping in their flower box. One thing I hate more then shooting a pet is irresponsible pet owners, and that includes cat people, you want to let it run wild at night because it is a "cat" well guess what if it is in my chickens and killing my livestock it is getting a bullet in its head pet or not. Be a responsible pet owner.