Well level disign/difficulty managment is the long part (ie hard to do in a jam)
maybe make a rigged random ball taking :
until the 5 or 10th turn make that the ia take 4 or more ball each turn; or fill half the remaining board each turn; or anything else
BUT the balls NEVER falls on the player
Then when the turn limit clicks let the ai be fair so the game os neither too short or too long and let the player feels somewhat cleaver
Ps I didn't know I could kill a chess pice ? do you mean lvl or chess piece by "enemy" ?