An RV trailer with a 9,000 LB GVW will have more than 900 lbs of tongue weight.
Likely in the 1,000 to 1,200 lb range.

Keep in mind, that 900 lb listed tongue weight is for a completely empty trailer as it rolled off the assembly line.
That is before the propane bottles, batteries, and any other options like a second AV were added.
Then you of course will be adding your own stuff (kitchen supplies, bedding, camping gear, etc.)
You will never pull that trailer at that assemble line weight again.

Remember, you are not supposed to go over "any" of the limiting specs your truck was built with.
For a 1/2 ton truck, you will reach the Payload limit before you reach any max towing limit.
Payload is (trailer tongue weight, all people in the truck, any other gear in the bed, plus the weight of the weight distribution hitch)
Add all that up and you should not exceed what the listed payload is for your truck. There is a sticker in the door jamb that lists the payload.

Of course that 3.0 diesel has the power to pull it, but is the rest of the truck is still 1/2 ton rated.
Max towing capacity is one of the most misleading terms out that when it comes to RV trailers.
They are "tongue heavy" and its like pulling a giant sail behind you.

So, what does the payload sticker for you truck list?

For the towing scenarios you listed (7 miles each way, only twice a year), I imagine you can go over some of the specs.
You have to be somewhat concerned, other wise you wouldn't be asking about air bags and only pulling twice a year for 7 miles each way.

 

Yes, GM's rating labels are for the scale weights for truck/trailer as loaded when connected to trailer.

GM's door 'rating' labels have tongue weight ratings at 10% of trailer weight for conventional trailers, 15% for 5th wheel/gooseneck.

On a 1500, the 5th/gooseneck rating is usually less than the conventional rating -- limited by the rated tongue weight for them.


GM knew that the truck would have ARC when the (serial number specific) load/trailer rating label was printed.

For 7 miles just hook it up, confirm the trailer brakes are working, set the braking gain and go...

 

If towing than you should be using Tow/Haul mode, it will work with ARC.