I've tested V1.9.1 on one of my Rigs with 6 RX VEGAs and it is stable after 1 day and a half of mining.
if it goes without any error for two or three days, then i will start to set it up on all of my Rigs.
proof: https://i.ibb.co/DW4XrYt/Monero-14-July.png