I've had many roosters during my lifetime. Some very docile, others terribly aggressive. From my experience I have learned they do not like water sprayed on them. I have a spray bottle filled with water that I carry and have handy near the chicken house for such occasions. My chickens free range inside the fenced in area of about 5 acres, but they are closed up in the chicken houses with a run during the night and at times when we can't be home to care for them. My little black cochin bantam rooster, named Rooster Pooster, sometimes wants to kick someone. He is my pet, but he does not like all humans. I keep the spray bottle handy when he is loose. You may try the spray bottle with plain water or you may want to add a bit of apple cider vinegar mixed in with it. For larger roosters I have sprayed them with the water hose in past times. It changes their attitude quickly.
And yes roosters can hurt you! Their spurs grow long if left untrimmed and rounded on the point. They can hit you hard enough for those spurs to stick into your body. Doctors will require a tetanus shot. They can be dangerous to children, and you as well, as they can fly up high enough to damage their face/eyes, etc. You need to keep up on the trimming of the spurs and the toe nails if they don't free range.