OK so managed to get from BUF-DCA a few days ago, arrived around 7:40am and went straight to AA check-in, asked for earlier flight on standby/change for possible weather and misconnect reason and while the agent said it's not technically allowed, but she was nice enough to confirm us (2) on the last 2 F seats on DCA-ORD at 8:30am when I was expecting just any Y seat since all flights were full that day. With pre-check and priority, were able to get in just when boarding started.

At ORD with 7 hours to spare, went to the cinema to watch a movie and browse the fashion outlet then back to lounge for a short while. Plenty of hotel shuttles to go from ORD to the area, Uber on the way back was $9, but likely higher due to the heavy traffic at the nearby convention.