Both work.  Different people do it different ways.  I do not understand the problem in taking him off of the roost at night and waiting until the next morning to butcher him.  They are not going to eat or drink in the dark anyway.  Some people starve a chicken for a while before butchering so they empty their intestines.  That way they don't worry about nicking the intestines and messing up the meat.  I don't worry about that, I just rinse the meaty well. 
The only possible problem I see is where do you put him until morning.  If you are afraid of an aggressive rooster it may be challenging to get him out of a cage.