For D9 owners who have not yet upgraded their firmware - consider this first.
The updated firmware does have a few bugfixes (auto tuning, rebranding, etc).
Notably your D9 will float between 2.35 and 2.55 Ghs - but understand that this increase in performance is essentially due to overclocking, and as such - Your power consumption will go from the advertised 900 watts to 1000+ watts. This will generate 3-8 degrees (c) of additional heat that you will want to compensate for. If you're already running them in a warm environment, you could now be teetering on the operational shutoff temperature.
Just consider it before you update.