I often don;t finish baking my loaves until 8 or 9 pm. How long do I need to wait before bagging them? I usually leave a towel over them and bag in the morning.
As long as they're at room temperature all the way through the crumb they should be read to bag. Overnight should accomplish that.
It will, of course, depend on what you mean by "bag" as the type of bag you use (paper, plastic, etc.) and whether or not you leave it open ended, losely closed or tightly sealed.