I don't wash my hands after handling my indoor/outdoor kitty unless I'm going straight to food prep or something else that requires stricter sanitation. I bathe her every two weeks, though XD
I also wash my hands thoroughly after handling her food or ANYTHING to do with her litterbox. Some vets/websites will scare you to death about toxoplasmosis, but you just have to be logically careful (use a scooper, drop the waste into doggy waste bags and tie them up, and wash those hands) and you'll be fine!
I would strongly, STRONGLY recommend a collar and ID tag AND a microchip for your little gentleman, even if you are 100% sure he is going to be a totally indoor cat. Long story short, I have a friend in Arizona who swore her two indoor cats were "never going to get outside ever", so she did not microchip or collar/ID either... and of course the second her brother accidentally knocked out a screen window, both cats ran out it in a flash. The same thing in fact happened to her cousin's cat as well, who was not collared/IDed, chipped, OR spayed! The cat ran out the door when someone opened it, and ended up coming home pregnant. Long story short, collars are perfectly safe (my girl's been wearing one for 17 years!) and even "oh he'll never escape the house" indoor cats should be collared, chipped, and IDed, for safety's sake. A breakaway collar is a must - and the good thing is, since your boy's going to be indoors, even if he "loses" his collar, there's only so many places it can be!
Another bit of advice I've learned over the years is - put away those cat toys when it's NOT playtime, unless they're of the really tough, unbreakable variety (like a ball-in-a-circle-track or something). Cats will be more than happy to shred apart those little mouse toys and eat every scrap of them the second you have your back turned, and it's not worth a trip to the emergency vet to get a string or feather removed from their intestine! ;} Plus, just imagine ... it's 2am... and all you hear is JINGLE JANGLE JINGLE from the cat playing with his bell-in-a-ball toys ;} I put away all my cat's toys except this thing, which she loves like you wouldn't believe:
An all-wet-food diet is wonderful! Perfect :} Kibble is horrible for cats and can cause all kinds of issues, especially in male cats. Grain-free canned is the way to go. There are a lot of good brands out there - as others have mentioned, you might want to have a rotation since a cat may suddenly decide he just doesn't want the food he scarfed to the last atom yesterday. My cat is on a raw diet, but I keep several canned brands on hand for the days when she decides, for whatever reason, she doesn't want to eat the raw! ;}
Make sure he has a few water bowls, too, not just one - put them in a few different rooms if you can. For some reason cats seem to like a variety of water dishes, and some even like water fountains.
Even though your fellow is going to be indoors, a flea preventative like Revolution wouldn't hurt and also helps protect against other parasites. I'm not sure about deworming as I have little experience with it (it's never been an issue with my cat; either that or it's not an issue in my area? My vet has never brought it up, heh)
If you're planning on grooming every day (which is fantastic!), you probably won't see a TON of shed hair everywhere. I suggest investing in a lint-roller or two for clothing anyway though!
Your boy might also appreciate a "hideaway" type cat bed or cat tree - maybe nothing too high since he is declawed and I'm not sure how well declawed cats can scale a cat tree, or if they still like the "feel" of scratching a scratching post - but a nice enclosed cat bed will probably be appreciated so he has a place where he feels he is totally safe and isolated if he needs to just be by himself for a while.
Otherwise it sounds like you have things covered really well!
Adopting an older boy means he likely won't be destructive like a kitten, and although he may be set in some habits/ways, he'll likely adjust to your family well.
One thing about enclosed litter boxes - they're mostly made for humans so we don't have to smell/see/think about the litter box. But the cat, whose sense of smell is much stronger than ours, may not appreciate going to the bathroom in a tiny, dark, enclosed space that already smells of his earlier trips to the restroom. If you clean the litterbox daily, for a single cat, you probably can go with an uncovered litterbox and he might appreciate it more. Unless he's like my cat and he's a litterkicker... her box is in the garage so I just sweep it out, but I can understand that's less of an option with an indoor cat. There are a lot of high-sided boxes out there, though!
Good luck and feel free to keep asking any other questions you may have! It sounds like you're well on your way though and your boy is going to be thrilled to have such a great home and family :}