I could have sworn I posted a response to your question but since it is not here, I'll try again!!

If your soil is workable, by all means go ahead and plant now. It is far easier to over winter a plant in the ground than in a container, even a large one.

And I wouldn't be overly concerned about any needed root pruning. The fall period of aggressive root expansion is pretty much done for the season by now anyway. And containerized maples are typically root pruned in winter prior to repotting as well. As long as your trees are dormant, they should settle in nicely and new root growth/expansion will resume when soils warm up again.

thanks for the response. i plant one today and i hope to plant the second next week. i plan to plant the second tree in full sun because i don't want two bloodgood on the same side of the house.
do you think its a good idea?
the tree will get sun for two thirds of the day.
its a mature tree, about 14 feet tall.