No one would be giving him a hard time if he was pulling said trailer with a 3/4 ton truck. But everyone is giving him crap for doing it with a "half ton".
Compare the payload and tow ratings of a 1999 3/4 ton vs a modern half ton. Aint much differences. And depending on how trucks are equipped, axle ratios and transmission etc....many times a modern half ton is rated for more than a 20 year old 3/4 ton.
Its the blanket statements that "you sould get a 3/4 ton truck cause it is better" that is the issue.
A modern half ton with 9000 pounds behind it is not excessive or exceeding ratings if properly equipped. And Id much rather do that than the same load behind a 25 year old 3/4 ton
Well I generally agree with you in full, but to be fair, it sounds like you are making some of the same over-generalizations in the other direction.
Just because some modern half-tons have high numeric trailer tow ratings, still doesn't make it a good idea to max them out on a heavy haul. One thing about old 3/4 ton pickups (like my '03 2500HD) is that the tow rating might be fairly low, but the
payload ratings were almost always quite a bit higher still. So you don't have to worry about excessive tongue weight so much, IE, the problem our OP is having. Furthermore the 3/4 ton trucks are heavier themselves, with heavier duty suspension, frame, brakes, hitch, transmission, etc. Add it all up and it makes for a much safer and more stable towing experience.
But on a half ton, you don't know whether some jacko on the road, or random internet person has a tow rating as low as 6 or 7000 lbs, or the max tow with 12-14k ratings nowadays (yikes). Or say a 2014 ram that might have a pathetic payload rating under a 1000 lbs, and really shouldn't have any weight on the hitch at all. So in general, and on average, it is true to say that you would be safe doing hauls like this on any 3/4 ton less than 20 years old, whereas only the top 10-20% of half ton configurations would be appropriately rated. You're right that many of them can do 9000 lbs safely now. But with a trailer like the OPs.... you can accidentally have a 13k lb load, or 2500 lbs on your hitch, which no half ton should do.
My 2003 Sierra 2500HD is only rated to tow 10,500 lbs because I have the lowly 6.0L LQ4 gasser. But! The very same chassis would be rated at over 18000 lbs if I had the duramax, so mine is essentially just de-rated for power and marketing considerations.