I'm glad you made the decision not to take him. Of course, it would be better if someone could take him and get him off the streets. If that's not possible, having him checked out at the vet and get him shots and neutered if he's not would be the next best thing. Thank you for thinking thinking to have him seen by a vet for a checkup, shots, worming, etc. that would be wonderful.
There are a lot of racoons in Toronto and yes they love cat food. As well as there are other stray homeless cats likely around as well. You can't guarantee that only this boy will get the food, if that's your intention. Cats are creatures of habit and routine and if you always went or someone did at the same time each day to feed, I'm sure he would be there waiting for food and probably some of his friends too. A waterproof box with shredded newspaper would give some insulation and warmth.
"We humans are indeed fortunate if we happen to be chosen to be owned by a cat." -- Anonymous