You'll have no trouble towing that trailer with the 5.7 Grand Cherokee. My Jeep tows the Starcraft very well. You should be equally well matched with your bigger trailer because you have significantly more horsepower and torque than me.
2007 Toyota Tacoma, Double Cab 4x4 Max Towing 6,500lbs GCWR 11,100lbs
2011 Jayco X20E, Pro Series 800lb Weight Distributing Hitch
Husky Sway Control Bar, Prodigy Electronic Brake Control