IME, when VW hits a Japanese maple this young, the result is fatal and fast. Like virtually overnight (2 or 3 days) to a week at most. It certainly won't hurt to leave as-is in place over winter and see what happens in spring. Any deadwood can be removed at that time (sterilize pruners between ALL cuts) or the tree could be completely gone or completely fine. I am inclined to think NOT VW because of the only partial wilting/dieback (usually see that on much more mature, established trees) and the lateness of the season. But symptoms are not alway consistent so it is still a possibility.

btw, this forum gets very little traffic. You might want to post any updates or further JM queries on the Maples forum.