Okay, I'm going to get crucified for this, but I can tell you that these babies are a whole lot smarter than mommies and daddies realize, and this little fellow is exploring his boundaries, seeing how much authority he is allowed. As parents, or even child care givers, adults need to provide the limits.
He is old enough to understand consequences for unacceptable behavior and praise for acceptable behaviors. If he will not listen to you, continues to wiggle, kick, and make it impossible to change his diaper, there are several options. Try putting him down, leaving the diaper on him and ignoring him TOTALLY for a minute or two. Try again and repeat if necessary, emphasizing the NO each time. If he becomes angry and kicks more a slap on the thigh or bottom, not enough to hurt anything but his inflated ego, often times can get their attention and cause them to rethink their actions. It may take several times of doing this but consistency is the key. If EVERY time he does an unacceptable behavior you use the same consequence, he'll quickly get the message, and know YOU are the one calling the shots NOT HIM.
If you continue to allow this, it will escalate to other negative behavior and he'll expect to be allowed to do whatever it is he wants to do. Create boundaries and stick to them.
1-2-3 Magic works well, even starting at one year, kids are amazing and very quick to see what's expected of them. We don't inhibit their creativity, freedom, or safety by doing this, it's for their development and learning about right and wrong, good and evil, yes and no, it's for their protection, well-being, and yes for the parents, too!!!
So my advice is to be the parent, teach him with love, make the boundaries clear, and BE CONSISTENT. It'll make home life much more enjoyable as time goes on, and establish a healthy bond between child and parent.