Grinding noise

First of all, did you wipe off the dip stick before you used it to check the oil level? Oil splashes up high on the dip stick, and that will give a false reading if you do not wipe it off first.

If oil could cause a grinding noise, it would have done it right away when you left the shop, not two days later. The noise also wouldn't stop after thirty seconds. The level does not get lower on its own.

A better suspect is a plastic splash shield became mispositioned during the service and was overlooked. Now it is rubbing on something when the engine rocks during acceleration. The place to start is by returning to the shop that did the service and give them the opportunity to correct any mistakes. They will double-check the oil level too and correct it if it is wrong.

Yes, but I'd avoid hard acceleration and unnecessary high speed. The goal of part of the oiling system is to spray oil onto the cylinder walls and other moving parts, but it also has to be under pressure to isolate some moving parts from each other. When the level gets too high, the oil can be hit by the spinning crankshaft and get air whipped into it. Air can be compressed, and when it gets into the pressurized oil, it prevents it from preventing metal parts from rubbing against each other. If the bearings start to wear, they will tear apart in short order, leading to the need for a total rebuild.

An inch overfull is not desirable, but it's not severe. There is some safety margin built in to allow for slightly over-full oil level without causing a problem. Keeping engine speed as low as practical will lower the chance even more of the oil being hit by the crankshaft.