Ford does still offer 3.73 gears with the 6-spd, I think even with the current 2016 Ecoboost. The tow rating for the 3.31 gear is not 9000 pounds, but the 6-spd should make little difference on the rear axle.
As you shop, please check the as equipped payload per the this sticker on the driver's door or door jam:
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2009+ Ram 1500's tend to have lower paylaod than most other half tons. The two trailers you listed should be in the 6000-6500 pounds range when loaded for a long weekend with about 750-850 pounds of tongue weight. Say the family weighs 600 pounds. It makes a difference if the tow vehicle has 1000 pounds of payload or 1500 pounds, which are both in the range of Ethe half ton pickup and SUV market.