8-9% is about where my wood levels off too after many years in Colorado, where 2/3rds of days are sunny and dry. Technically the front range is considered a semi-arid desert.
There's a learning curve to these stoves. It sounds to me like your cats are plugged. We've plugged ours twice. It's no big deal. Finish the burn cycle in bypass mode. When the stove has cooled, lift up the stove pipe or remove the rear flue cover to have a look, or remove the baffle in the stove and reach in from the front, either way.
I use my ash vac to clean them out, reinstall, then back to burning and everything is fine.
It's important to burn hot clean fires in these stoves to keep the combustors clean. Full loads of dry wood burned at a steady pace that brings the stove to high temps for many hours are good, small loads or slow feeding or wet wood at lazy burn rates are not. The manual on these stoves suggests 35-45 minutes once or twice per day of burning with the cats engaged and air control in the full-open position for a rigorous hot fire that will not only help keep the cats clean, but also keeps the chimney clean.
My normal startup routine includes leaving that air control open, cat engaged, until the EGT's are around 800F for several minutes before choking down, most large loads of my soft dry wood will continue to drive 800F EGT's for 30-60+ minutes after that startup before settling down so in my mind that's my "cleaning cycle." If you're burning harder wetter woods choking down that early will probably just pull the burn rate down and the EGT's down rapidly. Leave it wide-open for the recommended 35-45 minutes or until the stove temps are hot. Don't be afraid of 700-900F EGT's during startup/cleaning, that's the ticket to keeping things clean. Most stove pipe and chimney systems are rated for continuous operation at 1000F, and will easily handle temporary spurts to 1200F from an accidental overshoot once and awhile. Low EGT's will cause you more problems than high EGT's in most cases.
If you prefer not to perform this clean cycle burn on a full load of wood (there is a risk of runaway if your draft is too strong), a small load of dry thinner splits (or branch pieces) piled up at the front of the firebox over a bed of coals in an already warm stove can be burned through in the full open position, like a dedicated "cleaning cycle" for the stove. This rapid burn off of a small load of fast burning thin splits should last about 35-45 minutes of intense flaming, driving the temp gauge on the stove to near the maximum "active" range, leaving your cats looking like they are brand new.