Crashes are DCS related, try running a repair.
The Squadron doesn't respond to the built in radio menu. You need to use F10 - Attack Primary. If they don't attack, maybe they can't see the target. Your alter ego does not order them to attack, maybe it was another flight?
Wait, in Mission 9, the briefing says:
"Once we reach the target, Whippet will go in first, while Platform gives us cover. Once we're clear of the target and regained altitude, then Platform goes in while Whippet provides top cover."
So you need to wait for the 61st to engage - that was Gabreski you heard on the radio, ordering Whippet to attack. Before reaching the target he even says:
"Fairbank here, we're approaching the target, get ready to attack. I'll take Whippet down, Platform, you circle above to cover us until we complete our run. OK?"