Answer: Unfortunately, based on your description I am not certain what is happening. Over-watering would not cause holes, but it might cause yellowing. Premature fall color due to drought stress could cause some yellowing also. The holes might be caused by Japanese beetles or by hail damage or by some other insect.
In terms of watering, your goal is to supplement rain --if needed-- so that the soil stays evenly moist but not sopping wet or saturated. To know if you need ot water, dig into the soil with your finger. If it is still damp, do not water yet. When you water, water slowly and thoroughly so it soaks down deep. It is better to water deeply less often, than sprinkle lightly every day. (The deeper watering encourages deeper rooting ot where the soil naturally stays moister longer.) After watering, wait a few hours and then dig down to see how far the water went; it ca be surprising.
Since this is a new tree, I would suggest you consult with the professionally trained nursery staff where you purchased it and/or with your local county extension. They may appreciate a photo of the overall tree and close-ups as well as possible a sample. If it is something that requires a chemical control, your county extension will have the most up to date recommendations on what to use and how/when is best to apply it. I hope it is nothing serious.
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