I was a young beginner software engineer, and was out of town when it happened, at a bootcamp for MCSE studying. We had nothing to do but keep going with our studies - we couldn’t fly home since air traffic was all halted - so we just put our heads down and tried to focus on the task at hand.
I have never in my entire life been so glad to be home as I was at the end of that week, though. Homesickness for Eugene was roughly 1000% higher than at any time before or since.
I was in undergrad in Corvallis. I slept with the radio on in those days so I woke up to the news about the first plane while there was still hope it was an accident.