Birchmere shows start early. The Jenny Lewis show has a 6:00 door and a 7:30 start time. Shows at the 9:30 club start later, and 9:30 may well be the time the doors open.
One night I saw Lhasa play at the Birchmere, then bolted across town to catch My Morning Jacket at the 9:30, and I didn't miss any of either show. Of course, MMJ was the headliner and The Elected are openers, but I'm guessing that even if they end up cutting it close they'll make it there in time. Either that, or Jenny has made other arrangements for the night/tour.