I see, you don't know what you are talking about. K9 dogs are police dogs. Police has resources of volunteers - is it where you intend to work? You should join a Schutzhund club then, when your puppy is three months old, pass obedience there first (at 6 months) and they will tell you if your dog is up to at all, train your dog in socialization with people and other dogs in the club before he is one year old, only then you can approach kids without a muzzle. K9s bite only because their handler told them to, not because they want to.
I do obedience at 9 months and no bite work before a year or more, unless it is a game of tug. And yes they do but it is directed