Grab Process Monitor and watch file/registry activity during this 8-12 second wait.
I bet there is some path, file, etc. that AutoCAD is asking the O/S for, and it can't find it, hence the delay.
Another quick test is to unplug the network cable, disconnect all WiFi connections, etc., and test again. If there are no network connections, Windows will not have a delay when looking for whatever. It gives up immediately.