Well, for that age the drills those kids need to be doing are fundamental Fielding, Throwing and hitting drills. Im not to sure if the ones that I know are apprropriate for kids that young, Most of the ones I have memorized are from highschool baseball....But to give you an Idea....
Hitting-Get a some tennis balls and softly toss the balls to the kids and let them hit the balls into a chain link fence (works wonders for hand Eye cordination)
Also there is nothing like hitting a ball off of a Tee to improve hand eye cordination either, get a few Tees, and set them at different heights and get the kids to move from tee to tee
Fielding-Nothing beats good ol' infield/outfield practice, just have the kids go to their respective positions and hit them various balls ex. Ground balls, Fly balls, Line Drives, Slow Rollers, you know the basics (this drill can be made easier with a pitiching machine aimed upwards for fly balls)
Throwing-Before practice just make sure the kids warm up real good by tossing the ball back and fourth a few times, and make sure that you get your outfielders in the habbit of hitting cut-off men, and make sure that your third bassmand and short stop have a good enough arm to throw a ball accross the diamond, as well as a the catcher.
Just some quick free random baseball knowledge that I have pent up in my head from years of playing, though im sure you already know most of this
