I don't do the ball dividing deliberately, one thing I do practice and suggest that other do (say on my league team), is to practice getting position on the 9 ball on the spot and lower. Almost all the time the 9 is near the spot, or goes back to the end rail. Which means you need to play position to those areas a lot to win. Many matches lost by medium level players are lost after they run 4-5-6 balls and then get bad shape on the 8 or 9, so learning and getting comfortable playing position for the last 2 balls is very important.
The end game is vitally important in nine ball. You shouldn't run eight if you can't make all nine. I practice the eight to the nine a lot. I'll do this thing where I'll throw the eight nine up on the table and leave myself out of line on the eight and practice getting tough outs. Once I do this ten times, I'll throw the seven and do the same thing, leave myself out of line a bit and make the recovery. Then it's up with the six and so on and so forth. A miss is game over and up with the balls. This gives great practice getting back in line. One of the hardest things is staying in line as you get less balls on the table, especially if the spreads are odd, balls on opposite ends of table or frozen to rails etc...