If I accept an AGR supply sergeant position in the ARNG, how long is the 92Y MOS school through the Guard (if I can get dates to do it)?

Short answer upfront: 8 weeks at Fort Lee, Virginia. AGR would most likely send you to the active duty course. There is also reserve and guard reclass training at multiple sites around the country that are usually two week Phase 1 and two week Phase 2 given at places like Camp Pickett, Virginia.

I am a 92Y AGR that had to reclass once I got my job and was fortunate enough to get my phase one and phase two back to back. Even luckier to get the school house at fort schafter flats Hawaii, so a month in Honolulu Hawaii for a school when can I go back.

look up ATRRS course catalog, it should tell you.