I've never seen 9/7/5 UX Double Bonus. The game would have to be around 100% because the 9/6/5 listed on Wizard of Odds is 99.04. Wizard also has the strategies for these games. But he doesn't have 9/7/5 listed. He's showing 9/6/5 as the best payscale.
Looking at the strategy, the 9/6/5 UX DB strategy is almost the same as single line 10/7/5 DB strategy.
So if you have a 9/7/5 version of the game then you are going to be holding 3 card flushes whether they have 1 or 2 high cards in them.
https://wizardofodds.com/games/video...es/ultimate-x/
Links to the strategies are at the bottom of the page.