Lets say I have 2 aggressive fish both sexually mature, I divide the tank and place a plate designated for the female to lay her eggs on when ready, if I lift the divider and moved the plate over to the male side would he fertilize them or not ?
No, the fertilization need to occur while the female laying eggs. If you just move the eggs over to the male side after the female done with it then eggs will become a free snack for him.
If you have 2 very aggressive fish, you can use egg crate to separate them. Put a flat rock next to the egg crate on the females side, and if you are lucky, the male can often fertilize through the egg crate.
above is the female with eggs on one side.
Below the male sending milt to the other side.
It is always a good idea to have the female downsteam from the water flow, so the milt flows over the eggs.