Yes you will be overweight, severely. Tow ratings are useless numbers as you will almost always exceed most other ratings before getting anywhere near it. You need to be more concerned with the trucks payload and axle ratings. I don't know details of your specific truck but I'd guess you're probably around 1500lbs. Check the sticker on your door jamb to see what your payload is. Subtract the weight of all passengers and stuff you will carry in the truck plus another 200lbs for the hitch weight. What is left (won't be much) is what you can afford for the pin weight.
Most fivers carry between 20-25% of their loaded weight on the pin. A 9000lbs dry trailer will easily be over 10k loaded, putting well over 2,000lbs on the pin. That's well into 3/4 ton truck territory. Only a few of the smallest and lightest fivers are 1/2 ton towable while staying within ratings.