Its not a foul, however if the six ball or any other accidently makes contact with the cb it becomse a foul. The six ball would remain at the spot where it comes to rest.
11.g: A game is forfeited if you alter the course of the cue ball or the 8 ball in a game losing situation.
The above rule obviously is from the 8 ball section. There is no mention of the situation in the 9 ball section.
They don't say anything else about it. We have always played that moving a ball in motion is the same as not in motion. The opponent puts it back where they think it would have gone. Don't like where they put it? Then don't contact the ball!
