For those of you who do USSSA slow-pitch I have a question.....Rule 8-5-A states "Baserunners are out when a baserunner fails to keep contact with the base to which he is intitled, until a pitched ball touches the ground, has reached or passed Home Plate or is batted". There are 3 choices there. Which one is used when? I was watching a game where the ump called the runner out for leaving too early and the runners argument was that the ball had already passed the plate when he took off (the batter made contact with the ball). So based on that play it was from when the ball "is batted". Makes sense, but what about those other 2 choices?

I don't do USSSA, but the same criteria basically apply for the games I do. As I understand it:

A pitched ball touches the ground - this is used to allow runners to release for a bad pitch. When a pitch gets away in softball it often hits the ground 5 feet from the pitcher. The runner is not obligated to wait until it gets to the catcher before he can try to steal.

A pitched ball has reached or passed Home Plate - If a pitch is not offered at, when can the runner release? Some codes say when the ball is relased, some say when it reaches the batter, or the plate. In your case, "when it reaches or passes home plate" can be restated as when it reaches, since it cannot pass without first reaching. This is the toughest to judge, because even in slow pitch, the amount of time elapsed in the last 5 feet is miniscule. As a guide, if the ball is anywhere in the area where the batter could reach it, even in front of the plate, it has arrived.

A pitched ball is batted - this one is simple enough if it was the only criteria, i.e., pitches were always batted.

In your case, the runner was called out for leaving because he did so before the batter made contact. The runner believed his action was legal because he waited until the ball reached the batter. I'd have to agree with the umpire here. It should be conclusive that until the batter made contact, the ball had not reached him. Otherwise, he'd be able to hit the ball before it arrived. Whether it reached the plate before it reached the batter is irrelevant in interpretation when the ball is hit - the difference at most is measured in hundredths of a second, and you just have to use the umpre's judgement over the runners.