How big was your garage to start with. In many cases these days no, 8 inches is too much to lose.

You need to include the dimensions of the garage as it would be with the error/fix and the size it should have been.

Have a floor/foundation plan? One OH Door or two?

You need to figure out if the fix is acceptable to you? Will it effect your usuage of the garage? Will it effect the timeline of your construction negatively for bank financing or town permits? Is he offering any monetary concession since you contrctaed for a larger garage than you are getting?

Yes, here is a screenshot of the area in question. The top left corner of the garage wall, which is a poured wall to the basement, is poured correct. The top right got poured 8 inches into my garage. My contractor said he would make the utility room bigger and fix it with the framing.

Have him add a utility sink in your laundry room instead.

At least you will have one good thing out of it, you will lose 8" of storage in the garage but you will gain 8" of living space... I see a stairway there, ask for wider staircase plus you will have a wider hallway, etc.