The tech only said that the 9000XL can be dialed down to a softer ride when the camper is off the truck, where the ride with the 7000MT will be firmer.
If you read the description of the 7000MT on the Rancho website, they do mention it is made for trucks that haul with a high center of gravity. Sounds like a TC would fall into that category.
The 9000XL description only heralds the adjustability of the shock, not their particular applications.
Since adjusting the 9000XL would be a royal PITAS on my dually, I am going to try a set of 7000MT. I will get them installed later this month and will report back as how they compare to the OEM's and Bilstein 5100's.