SpaceX Dragon was designed to fly 7 in a 4 + 3 two deck setup. For the love of all that is holy just send up crew 9 with the second row installed. Once at the ISS use the robot arm to move and hold that junker of starliner out of the docking port long enough to pull the seats and put them in the already docked Dragon then fly home with 4+2 in that Dragon. It’s not rocket science...or use the fact that Dragon can fly itself and undock the existing Dragon fly it a few Km away and hold just like they do for every normal arrival. Then fly in Crew 9 dock it pull the seats and undock it swap back in the other Dragon and fly home with 6. The absolute simplest is to fly Crew 9 with 6 seats and use it to bring NASA guys plus the older Dragon crew home home leaving the other Dragon to fly home Crew 9 Dragon has like a year of endurance docked to the ISS that older Dragon can just stay longer. This last way means dumping the Boeing turd for docking space before crew 9 gets there.
Nah just undock the empty starliner and let it burn up on re-entry