I understand your concern about crating your pets. 9 hours is a long time to either not have water (or for your cat to not have access to a litter box). Cats are noctural creatures, meaning that they are naturally more active at night so you are confining him during this part of his days.
For dogs, crating is often done, especially during the puppy stage and is safe and well-accepted. For cats, you should go by how your kitty is doing. If he is resisting being crated, perhaps crate him later at night (if you can) so that he is quiet when everyone is sleeping. He will probably stay in the same pattern even if he isn't crated. I just worry a bit about the lack of water for 9 hours at a time for both dog and cat.
Is is common to crate dogs, but usually 8 hours is considered long enough (unless they are travelling on a plane, for example, that takes 10 hours). I crated my puppy for her first year, and she liked her "bed" and went into her crate willingly on her own each night. Now, however, I let her sleep where and when she wants. She is usually on the bed with me, asleep, but sometimes, she gets up and chews on a toy and I want her to have the freedom to do that. Sometimes, I wish I could crate my cat because she is typically nocturnal and more active (and annnoying) at night but after 18 years, I wouldn't be able to retrain her -- so maybe you have a good thing going!!
Think of it this way: would you do the same for your kids? Would you want your child (or pet) to be thirsty for that long? I would worry more about older pets who need regular water to keep their kidneys
working (even if they aren't urinating, animals still need the water to keep the kidneys flushed of toxins). But I can't give you a hard and fast determination. I think it's important to watch your pets closely when you release them from their crates in the morning: what is the first thing that do? Drink water, urinate, what to play? Use that as your guideline and then adjust it as they become older.
I hope this has been helpful.