Here are a couple really solid CP grinding areas in Chapters 8 and 9.

The first spot is right after the attack on Hope's home in Parumpolum in Chapter 8. There are two sets of soldiers who will keep respawning inside the house endlessly. All you have to do is run down the halls a bit and they come right back and they will be there again. Defeating them yields a good amount of CP, and they drop incentive chips which you can sell for 2,500 and buy upgrade parts for your weapons.

I maxed out all my players and upgraded Lightning's weapon from level 16-22 in only 40 minutes of fighting.

The second spot when you're going to rescue Sazh and Vanille in Chapter 9. After you finish the outside fighting portion on the flagship you head inside; in there you get a "green alert" warning the enemy to your presence. Instead of proceeding further, go back outside and you will see that the enemies have respawned.

In fact, just right outside the door you will get into a battle with five enemies which nets you over 700 CP each time as well as dropping Silicon Oil plus incentive and credit chips. After each fight, head back inside around two corners to respawn the enemy. Do this as many times as you want and head inside to the save point to sell the chips and upgrade your weapons and you'll get everyone to level 3 of all their roles in no time.

I prefer these two places becuase of the incentive chips.