Well, III Ball, welcome to the forum, with a little good-natured ribbing.
It really is about preference and the kind of "feel" you want from your shaft.
I am still on this journey, but I am developing a preference for a stiff hit, even to the point of ordering a new 13mm shaft with a straight taper. I believe I can get sufficient English on the ball with practice. I have decided to go thick, because I can always have the shaft turned down thinner (in stages) if I do not like it thick.
I strive to play for position in every game, so I do not make a distinction for 9 ball.
Good luck, and make use of the older forum posts. You can learn a lot here if you can filter through the "religious" arguments.