Where I sail with kiters, there are waves involved and it is mostly always an onshore wind.
I try to get upwind of the kiters and usually stay there till it's time to come in. I find I can point higher into the wind than the average kiter so I usually pass them to windward. Very few of them come out where the boarders go.
When I am coming back in you have to be aware that they may not see you or be struggling with control over their kite (which is one reason why they stay in close to the beach). Be aware of what their kite is doing. You usually can see their intentions in time to give you warning. Be prepared to bail out if you have to as well.
Passing them to leeward can be tricky, especially if they are noobs and are having control issues. I have been cleaned up once by an out of control kiter but luckily no injury or damage. He was very apologetic. We say hello all the time now.
I the past I have also tried to help kiters who were in trouble with inverted kites or losing their boards, but you really are limited in what you can do except keep an eye on them and make sure they don't go under. Have got myself into some serious trouble once before when trying to help. Did major damage to my sail and almost drowned myself. Oh well, at least I survived another day in the waves....
Saw a kiter putting his wet suit on over his boardies on Saturday at the beach, so I asked him in jest why he wasn't putting them on over the wet suit and he said "Because I'm too fat for the boardies to go over the wettie". Fair enough......