How can I possibly keep a tenth cat?

How big is your grandparents' home? If the house is large-ish, you might find it possible to keep the one cat confined to one floor, and let the others have the rest of the house. Even one big room might do ok for the one cat, but that is not ideal. It will take him some time to adjust to being a strictly indoor cat, but the move may actually help with the transition. Another key to changing his lifestyle is enriching his environment to help him be happier and healthier indoors. Here are some suggestions to enrich your cat's environment. Give your cat more things to do by itself. Yeah I know, he's already got a million toys, right? Try putting away all but a few, and then rotating them every few days so they seem fresh and new. And don't forget to give some things to hide in and climb on, like a nice climb-able cat tree (I recommend the kind wrapped in sisal rope over the carpeted style), a paper grocery bag, or a cardboard box. If money is short, you can make a tree yourself - my boyfriend made one out of scrap lumber, 6in diameter pvc pipe, and some sisal rope; I'm not that handy, but I have made some kitty fun houses by gluing strong cardboard boxes together and cutting holes in between them so the cats could climb around, attached some burlap to one side for something to scratch at, and put a few toys inside. Give a couple of different bags or boxes at a time, so s/he can dart from one to the other. There are toys that are made to dangle from door knobs or from the top of the door. Catnip pads are great, too. Try one of those toys that drop treats as the cat plays with them. Consider changing how you feed kitty - instead of food always at one location, what about putting several small portions in different locations, for her to explore, hunt and find. Don't forget the value of birdwatching - if possible, put birdfeeders outside of your cat's favorite sitting-windows - instant CatTV. And don't worry too much if squirrels get to the birdseed - squirrels are fun to watch, too.