Agressive rooster can do some serious damage especially to children.Haven't tried this myself, but I've seen some people succeed by carrying a spray bottle with vinegar in it and spraying the rooster every time he rushes/attacks. Doesn't hurt him, but chickens hate vinegar.
If you use a spray bottle he will learn not to attack when you have the bottle in your hand. So each and everytime you are around him you will have to carry it.
The first time you forget, he will attack at full force.
It is difficult to do chores and enjoy your flock an keep an eye on an aggressive rooster if you have to always carry something to defend yourself.