Some tournaments now play "Shoot all nines. Concede the nine and you lose the next game also." I've heard of a match in which a player conceded the nine that put his opponent on the hill. He didn't know the rule was in effect and he was a little surprised to find out. It's good to pay attention at the players' meeting.
I don't think Larry was intentionally moving on Johnny, FWIW.
I agree about Larry's intentions, his emotions are plainly visible. He made an excellent break, only to see the CB get kicked in, and to add insult to injury, the 9 hang up in the pocket. He reacted with visible frustration, and conceded the game because it was easier than watching Johnny execute the certain win from there. There's not much wrong with any of that if the rules allow conceding games.
-Andrew