You may be a bit over the conservative 9200# GVWR but not even close to the axle rating (which is the important one). I hauled an 11K 5th wheel with that exact truck and it was a dream. You'll love the way the 5th wheels tow. I've gone back and forth over the years and am back in a 5th wheel with no plans of going back to a TT again.
Also, nice choice on the 5th. That exact unit was on my short list but I couldn't find one close enough and ended with a bigger/heavier Keystone Hideout 308bhds. It runs about 10,500# loaded up - weighed 9040# dry.