Marginal (and probably unsafe) at best.
Here's why.
If the dry weight of the trailer is 6600 lbs, the "loaded, ready to camp" weight will be 1,000 lbs heavier. That leaves very little margin for the least concerning "tow capacity" specification of 8500 lbs. More concerning for you should be the ridiculously low payload capacity these GM full size SUV's have (around 1400). If your trailer is ready to camp at 7,600 lbs (and properly loaded), you'll have about 1140 lbs on the hitch (15% of your trailer weight). Remember, every pound of weight applied to the hitch on your SUV directly takes away from payload. 250 lbs of isn't much leftover considering you'll have another 100 lbs taken away by means of a WDH. Think about how you'll allocate the 150 lbs remaining to you, your spouse, your kids, your dogs, your SUV cargo, your cooler, and anything else you want inside the Yukon. Don't even think about taking any toys or gear.
And I haven't even talked about axle weight ratings yet. Nor have I mentioned tire and wheel capacities. Wouldn't be surprised if you exceed these too.
Oh, and if your trailer is anything longer than 24 feet, you'll be in for a white knuckle surprise the first time you pass a semi truck on a down grade with any sort of crosswind. Hope you bring diapers.
If your Yukon is the non-Denali variant with GM's 5.3L Vortec aluminum block, good luck climbing any grades greater than 4-5%. You'll find your transmission wasn't built for any marginal towing experiences as internal temps will rise and you'll be revving the RPM's to compensate. I believe a trans cooler was NOT standard issue on the non-Denali version. Even the Denali version, the stock trans cooler was pathetic.
You'll also realize that a short wheel base SUV will do nothing to control your trailer. That's why longer wheelbase pickups are the better choice.
How do I know all this? I am a former owner of a Yukon Denali XL outfitted with larger engine, rear air leveling suspension, larger wheelbase and OEM and aftermarket transmission coolers (I had 2). My trailer was lighter than yours and my vehicle was more capable. I had to invest in a $3,000 Hensley hitch to eliminate the non-stop white knuckling I experienced on each and every trip. That severely put me over payload specs and I ultimately had to upgrade my TV. My new RAM 2500 Megacab has more than 2 and a half feet of addition wheelbase and tows the same trailer night and day compared to the Yukon. Yukons are nice vehicles. They can tow within their specs well. The problem is that payload and axle ratios will always be tested when towing heavy. I personally don't want to find out the hard way: at highway speeds with loved ones inside. A failure is catastrophic at 65 mph. Good luck.