If you want him to have good manners, he needs to be 'socialized' with other horses. If you do not do this, he will be much more difficult to handle and will start thinking and behaving like a breeding stallion at a much younger age.
We turn out all young stallions with older geldings. They put them in their place -- the very bottom of the 'pecking order'. At that position in a herd, they have very low Testosterone levels and usually act like a young gelding acts.
We have always run young stallions with geldings until they are ready to start breeding. If we have them stalled to be fitted, they get turn-out time with geldings. We just never raise them without 'socializing' them with mature geldings.
Most young stallions handled this way are nicer to handle, easier to manner, easier to ride and train and nicer as mature breeding horses than those that are not raised this way. It is sure the easy way to do it.