I was doing a null test between 8.5 and 9 and I did it wrong. One of the plugs was nonlinear (Slate VBC Grey) and generated consistent differences. They null perfectly. I deleted the topic,sorry.
actually, many plugins that null each other in other DAWS doesnt do the same in CUBASE.
I had the same thread in the ISSUES area, but nut surprisingly it was ignored
As long as the plugins are not nonlinear, the mixdown nonrealtime nulls perfectly. But regarding realtime sound, they sound different, I tend to say that c8.5 sounds more 3d, hi-fi and C9 sounds more saturated, aggresive. Now I’m used and I like 8.5 more for making decisions.