Manually select AF Point in Canon system

I am coming from Nikon system and I just picked up my first Canon (5Dmkii) over the weekend but I was wondering is there a way to manually select AF point without having to press that button at the upper right? In Nikon I could just change it with the arrow buttons (after I hit the shutter half way) while I shoot but I couldn't find a way to do that in Canon. Are there any other tips that I need to know in AF when I shoot with 5dmkii? I also noticed that there are only 9 AF focus point so I find it hard for me to manually choose a AF focus point that's right on the intersection of the rules of third frame..any tips on this? Thanks!