Caught two babies under carport when I was in middle school. Very cool pet when they are little, but as soon as those nutts drop, all they do is bite the shite out of you
Is the entrance to your attic inside your house only or is there one in your garage?
Because a cat is your answer if you can just leave the entrance to your attic open in your garage. No ladder down so the cat stays out of the attic. One by one the squirrels will drop down into the garage and the cat will get 'em.