The issue is that there are about 5-6 "official" rules depending on what people are asking about and about 10 other maybe rules that are in common use.
BCA, WPA, APA, USAPL, TAP, and others have rule sets that are "official" and to get a ruling one first has to know from what origination the question was from. Usually the good players are assumed to be playing by the WPA rules. However there are players that know nothing but APA or some other league rule and the "official" rules for them may be different. And when it comes to break rules, 9/10 on the break, game ball shot in last, races to win, all that goes out the window since even the most official of tournaments change that sometimes several times a decade.
For me, if I play someone that I know is a "player" I assume we are going by WPA rules with whatever modifications we make like 9 does not count on the break. When it comes down to what a foul is, I expect that to be pretty much universal outside of the banger level and some league modifications which I don't really consider "real" rules, but many people do.