Okay - I'm going to clear up some misconceptions about possums.
I've rehabbed them for years. Also squirrels, birds, bunnies - anything that gets injured somehow found it's way to our door.
I really love possums. They are the most difficult child-like critters known to man in that they will and should (for release) open their jaws, hiss and reveal about 50 razor sharp teeth. In all the years I've been handling them or taking a Mother out from under a house with babies I've never been bitten. They really don't like humans but once they find a food source in a suburb it's hard to get rid of them. Most of the trappers we know will come and get the animal and then by some exterminator law must kill it. Even the animal control will tell you that. If you catch and release they find their way back or it disrupts the balance of the area you release them in.
We've stopped on the road and checked pouches of dead Moms for babies to rehab. If you don't know what you are doing or don't have the time to dedicate to rehabbing - they will die so it's better not to wing it or try your best. If you find a little one? Get it to a wildlife center where they will get it a proper diet of (yuk factor of 8) most anykind of fruit, grasses, dead mice, carrion, snakes, beatles, earthworms, crickets, grasshoppers, they do like cat food....but it's not the best for them - they're just hungry and it won't do you or the possum any favors to keep the food out where it can get to it. Take up all animal food unless you plan on having a regular visitor like Daisy's. They will literally eat just about anything.
As far as carrying rabies? All mamals have the potential to carry rabies. But possums are not mamals they are marsupials and not carriers of rabies per se. Their body temps. are lower than mamals so that could have something to do with occurences of rabies being extremely rare. You're more likely to get it from bats, foxes, or raccoons than you are possums. You can check with the National Opossum Society. (yes there is such a thing)
I DO NOT recommend anyone trying to handle them but if you must go near them don't go without gloves. The best thing you can do is trap it in a baited live trap and then cover the cage with a sheet or towel - take it to a remote area far away from houses and civilization - and let it go be a possum. You also do not want for it to get used to you especially if you want it gone. Once they get acclimated to humans etc - they're not leaving and would do poorly out in the wild.
Possums don't seem to mind anything except loud noise (hence the hissing and mouth open - see me? I'm a BIG SCARY possum) and we say "Yes you are." and then toss a towel on him and put him in a cat carrier then take him to the far woods. The best time to release them is during the day so they can see where they are and find a place to hang before it gets dark.
They are North Americas ONLY marsupial. My best advice to you Janet is to get a trap - bait it with chicken (KFC FRIED OR GRILLED makes no difference) and once you catch him do not be surprised if there are more. ESPECIALLY if he's about palm size. Don't freak but Mommas can have up to 13 in a litter.
I tell you - SEND ME THE POSSUM. lol
