Similar to step 1 you could check all the other balls and see if they could hit the ball you want to go in a pocket. Then just see if you can make the second ball hit into the first ball with the striker.
Didn't look through all your code but if you need a simple A* tutorial then i reccomend this one. http://www.policyalmanac.org/games/aStarTutorial.htm Being in the 8th grade shouldn't stop you from learning it. Its fairly simple if you can visualize it. All you need to do is reread the parts that give you trouble and you should have no problem.
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