A few holes in the leaves from insects is really nothing to get overly concerned about.......this is more of a cosmetic issue than anything that can actually harm the tree. And at this stage of the season, it is too late to consider spraying for -- the tree will be dropping its leaves soon enough.

I'd be more concerned about the dried, crinkled leaves showing up in the second and third photos. These look like the tree is going through some sort of stress, either transplant shock or improper watering.

Mulching is always a good idea. Just keep it away from the trunk.