That 9200lb rating includes the weight of your truck loaded so take the weight of your truck out of the 9200. You're not asking for trouble, you're yelling "I hate Ns!!!" in the middle of Compton.
Seems kinda low to me...my 05 Durango, 4.7L 9.25 w/3.92s I think was around 11 or 12K towing capacity? I know empty, it was 5500 by itself, and I had my big block dakota on a U-haul trailer behind it, the dakota is 4200, the u-haul car hauler was 1500, so that's 5700 lbs right there, plus another couple hundred pounds of cargo in the back of the Durango and bed of the Dakota...during a military DITY move from Louisiana to Ohio, I had a weight ticket of 11 thousand and some change, and it made the 900 mile trip with ease. never got scary, even going through the "hills" of Kentucky, which can be pretty big! sure, pulling up some hills on the freeway, it was WOT, kicked down into 3rd gear and turning 4,000 rpm just to maintain 65mph, but other than that, it did great. (changed the oil immediately after the trip obviously, working it THAT hard for 900 miles)
The GenIII quad cab Dakota has the same motor, trans and rear end as the 05 Durango did, and weighs 1,000 lbs LESS.
as long as your trailer has brakes so the load doesn't get away from you, why COULDN'T you pull 7-8K lbs of cargo behind it?
However, I would be afraid of a cargo load of 9,200 lbs, add in the truck weight, some cargo (luggage, bicycles, food, other camping supplies) and you're pushing 14,000 lbs or more, which I would think is a bit much for the 4.7L