Imo if you're going to shoot the 9ball then you should play to position the 9ball close to your pocket. The other method of moving the 9ball just to position the cue ball in the stack is really not that effective, too easy for your opponent to escape from that position and also open up balls on his side. If there was a ball or balls positioned on the bottom rail then maybe just positioning the cue ball in the stack would be a better option. The gamble with shooting the 9ball toward your pocket is a good one when you consider that nothing goes in your opponents pocket if you should butcher the controlling of the cue ball, however, if you happen to hit the shot well you'll have a clear advantage. I would like to bring this point forward again, and that is, just positioning the cue ball in the stack is not always a good option, there are times when your opponent can develop a better position from your leave then he had prior to you shooting your shot.
There may be another option that would be very strong providing the balls lay good for the shot, i'll explain. It looks to me that the 2ball is lined up reasonably close to being pocketed by playing the 4 ball combination, if it is then playing off the 14ball and drawing the cue ball ..to the left of the 9ball.. if possible would be a very strong shot. The ending position you seek for the cue ball will be to the left of the 9ball, using the 9ball as a cover ball for the 5ball and 8ball. The key to the shot is positioning the cue ball where the 9ball is a cover ball. This shot will open up all balls (mostly on your side) and will give you a distinct advantage in ball position with a possible trapping position that could be very difficult to escape from.
Dr. Bill