Answer: I don't think the branch will mend itself so the kindest thing to do is make a clean cut (ragged edges can encourage insect and disease problems). A clean cut will callous over and your tree will make up for the lost branch by sprouting a new one nearby. Coral bark maples can take lots of hard pruning so you won't hurt your tree by making a clean cut. Next winter, when the tree is dormant, you can do some pruning to give it a more symmetrical shade if it appears lopsided.
Best wishes with your new maple!
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