First, you can't do anything but speculate about the trailer until you get it, if you use the numbers from the mfg. When you say 'pin' weight, is this a fifth wheel? 800lbs is low for the PW on a 6620 dry weight unit--if it is a travel trailer, then do you mean 'tongue' weight is 800lbs?
But to use what you gave us--go with the GVWR (9500) and use 20% (1900) as max pin weight for a fiver and 10% (950) as max tongue weight. Then compare these weights to what Toyota says your Tundra can handle.
However, if you tow a 9500lb trailer with a Tundra, you are going to feel some 'tag wagging the dog' effect without a Hensley Arrow or ProPride hitch. If it is a fiver, then a 9500lb trailer with possible 1900lb pin weight will probably overload the rear axle and possibly the payload rating.
Give us more actual numbers to help better.
And, welcome to the forum.
2016 Tiffin 40 QBH
2015 38RSSA, traded
2005 TK3 #1869, 10 yrs of memories,
2017 F450 KR--one more Ford is it
2009 F450 4x4-died; 2010 F450-retired