How are you asking him to canter? It sounds like a typical reaction of an annoyed horse. If I might offer a suggestion, find a way to not make it personal when you want him to go faster, instead of directing the pressure AT him, direct it to the space behind him so he can move out of that spot because you need it. Does that make sense? Same thins is pretty clearly demonstrated here. I feel like a broken record on this but there are plenty of other ways to get horses to move that doesn't make them so cranky.

Yeah you got his attention, but the fact that he went right back and did the kicking thing again is his way of telling you that little maneuver wasn't meaningful to him, it might have been the timing, it might have been the intent (ie if you were unsure). If you had not gone in and smacked him after the fact (just because?)  the bucket hitting the wall probably would have been more meaningful to him. As long as you keep him moving, keep his diagonals engaged, then he will not lose his diagonals to plant both front feet to kick out. That you refer to your relationship as a fight in unfortunate, if that is what you expect from your horse, that is what you will get from the horse. Horses are very keen at reading people, too much focus on the unwanted behavior and the horse things that is really what you want from them.

"It's really quite amazing what a horse will do for you, if he only understands what you want. 
And it it's also quite amazing what a horse will do to you if he doesn't." ~ Bill Dorrance