Seriously, this is annoying. Exact problem on my end.
You should not have to touch anything in network settings. Just make sure it is set to use DHCP.
For what it is worth the Tether app on my mac seems to crash too. It "seemed" to happen right after connection as it tried to load the tether.com web site (I hate that that happens by the way). But I always just start the app on the iPhone again and the relaunch it on my mb air and it is fine. Does not crash once up and running.
To be clear I start app fresh on iPhone first, then start the app on my mac.
Michael