Diamond-shaped 9-Ball rack?

Well, for 9 ball I've used both the standard rack and the diamond rack plenty of times. Personally, I always prefer to use the standard rack because I can always get a tighter rack with it, of course by using both hands to push the balls together inward. I also agree with your statement above, that the diamond rack tends to nudge the balls loose when you try to remove it. This is why I'm not a big fan of the diamond rack, and I certainly wouldn't go out of my way to buy one.

For 7 ball, the idea of turning the diamond rack sideways to rack the balls is great, I've also done this myself. However, it's not always necessary to just stick to using the diamond rack to accomplish this. Believe it or not, you can actually also use the standard triangle rack to get a tight 7 ball rack as well. All you have to do is lay the rack on the table at an angle, and put the cue ball (or any striped object ball) frozen on either side of the front apex ball, which would be the 1 ball.

Once you have all the balls in the rack, it might require just a little effort by using your hands to push the balls inward. When you're ready, slowly remove the rack, including the ball you just placed on either side of the 1 ball. You should now have a nice tight 7 ball rack. I don't play 7 ball too often, but when I do, this is the way I rack and it always works for me. All in all, the standard triangle rack is very useful in racking the balls for any type of pool game you're playing.

the diamond shaped rack is useless, using the standard 8ball rack is easier to rack tighter .since there is more space for u to take out the rack . that why in 9 ball competition they use the 8 ball rack instead of the diamond shaped rack.

put the 6 balls your not using in the bottem 2 corners so you make a diamond. then when you set up for 9-ball you can just take off the triangle and roll the 10-15 away and you have your diamond

If the 9-ball goes in off the break, it's game-over. This rack makes it less likely.

It is NOT easier to touch the rack, Not harder to rack 9 ball. It's just different.

its not necessary if you dont wanna spend the money. you can just use the triangle, but the diamond will make it look more official