The players need to know the things listed on the Rookie & Tyro curriulum, but they already know most of them. At the 9 year old level, you should add:
15. pitcher-cover-first-play
16. if bunting is allowed, how to bunt
17. if bunting is allowed, how to field a bunt
18. how to pick up a stopped ball
19. waiting for a good pitch to hit
20. rounding a base when running
21. one-throw double play (force or tag then throw to first)
22. one-throw double play (catch fly then throw to base of runner who did not tag up)
23. defender avoiding obstruction on extra-base hit
24. run-down (pickle) technique
25. oftern misunderstood rules
26. double-steal play
27. delayed steal
28. steal second on a walk
29. pop up and go to next base slide
This is an ambitious list, but doable if you do not run inefficient practices where you hit infield and take batting practice. Note some of the things that are not mentioned: