I know its not High School. I need help with a little league rule for the Juniors division. Specifically when and how steals happen, when does the runner need to commit? pitcher on the plate or in the circle? Etc.....

In Jrs. there are no closed bases so they can lead off whenever they want and can steal while the pitcher still has the ball. I suggest they not lead-off until the pitcher has toed the rubber, just to lessen the chance of getting picked off.
The circle in 90ft is only there for one reason and that is for the going to the mouth restriction.

Is this a softball question (circle vs. mound reference)

Runners can advance anytime the ball is live. Period. If you have a question as to when the ball is live that is another question that is more complicated.

For example, after a ball is hit foul or time is called by an umpire, the ball is dead. It is put back in play (Made live) by the Plate Umpire by explicitly pointing to the pitcher and calling play. This is done when the pitcher gets on the rubber and is ready to pitch.

Oh boy, trying to get the pitcher at the lower levels to recognize that the umpire puts the ball in play is another issue. I did CYO (7th and 8th graders) last week as a favor to someone and it took at least 3-5 times before the pitcher really knew that I was putting the ball in play. I finally started explaining it when a new pitcher came on the mound.

BTW, that wasn't coaching, it was preventitive umpiring. The kids were trying pick-offs with the time-out. That gets the parents going more than the kids.

I heard the runners have to stay on the base until the ball passes the batter. I also heard 2 things, 1. he has to commit to the base he has or to the one he is going to when the pitcher is in the circle or 2. when the pitcher is on the plate. Yes it sounds like softball but I have not seen the actual rule anywhere as I dont ump LL, and have no rule book. I do however coach little league as an assistant, and yes I keep my mouth shut on all calls. Anyone have the rule book?

PM me and I can help you out. The closed bases, not leaving until the ball reaches the batter, is for 60ft only. You said JrLL and that's 90ft.

Done