Bought an expedition with 24k miles. One tire was damaged so dealer replaced it. 3 have 9/32 and with 12/32. Dealer said this was close enough and I shouldn't worry. Thoughts? Truck is 4wd but not AWD if that matters.

Thanks

 

I would run them in a heartbeat. If it bothers you, put the new one on the front.
You will be in a slip condition when you go into 4x4, so it will not matter.

 

Even if 3 were nearly bald you would be fine. Don't sweat it.

 

You'll be fine. I have done that. As long as it's the same tire, it won't make any difference to handling or traction or safety.