The 3-row SUVs capable for towing 9000 pounds RV are all 7+ years old and get 12mpg unloaded. All thw 2007+ SUVs have receiver limits as high as 1000 pounds, which means more like 8k carefully loaded TT.
Dry cargo area can be had for any pickup for as little as $200. It isn't climate controlled, but it is covered. And a pickup will cost much less than an SUV with similar equipment.
There are 2 mid-sized SUVs that would handle your current RVs very well and get about 25mpg in mixed driving non towing. 2011+ VW Touareg TDI and 2014 Jeep Grand Cherokee Diesel. Lots of torque from 1500-2500rpm, where most people want it for both DD and towing. You can expect about 15mpg towing. That's as good as it gets from a fuel efficiency point of view. Owners of the 2007-2008 diesel Grand Cherokee and TDI Touaregs are very pleased with towing performance within their capabilities. But they leave little room for upgrading the RV from what you have now.
My opinion is to get one of the diesel SUVs I mentioned above and take a second vehicle when you need more than 4 people. At 25mpg vs. 17mpg non towing, you'll appreciate the diesel torque and efficiency far more often than occasional 7 passenger seating.
