I'm in zone 6 have many dwarf maples. Yours looks dehydrated and sunburned and it will recover. They don't like direct sun dappled shade they are an understory tree and roots prefer constant shade. Once established they are pretty tough trees. Fall is here and sunburn will leave leafs looking shriveled. This time of year they will lose some of the new growth stems. Wait till next spring to trim them off.
Other than the direct sun scald and fall leaves shrivel too, it looks ok to me.there is green on stems great sign. It has the winter to grow and strengthen the root system . Give it time and patience it will come back good as new next season . It looks like it's in a good spot for winter with some protection from cold icy winds.
First pic 5 yrs and second pic over 40 years old.