I strongly disagree. Cats have extremely dirty mouths, cat bites are serious stuff and even though the bacteria is present in their own system that doesn't make them immune to it. The idea that a cat (or dog) will "keep a wound clean" by licking it is a myth and one of the quickest ways to a hot mess that will require antibiotics. Animals aren't so very different from humans in that if a wound is bothering them they will bother the wound until it just keeps getting worse and worse. When it comes to skin wounds, there's no such thing as "good bacteria." Even the normal bacteria that is present on healthy skin causes infection in wounds. And with a cat that is licking at a wound we're not talking about bacteria that is "native" to the area to begin with.
If there's no sign of infection, I would avoid using a topical antibiotic (like neosporin or something similar). It may prevent air from getting to the skin and could actually slow healing. Also, the cat is likely to lick it off and ingest it. And while topical antibiotic ointments are generally not harmful to cats, they don't do any good on the inside of a cat's stomach. I would get an e-collar (you can get one at your vet or most pet stores also sell them) and use it until the wound has healed. Not much you can do about the scratching, other than trimming his nails. With dogs, putting a sock or bootie on the foot that they use to scratch the area can help, but it's pretty much impossible to keep these devices on a cat.