Flew through IAD a few days ago and had a chance to check out the VS Clubhouse at IAD.
Showed up at ~820pm with the VS flight departure listed at 925. Apparently they start boarding the VS flight very early because I was informed the lounge was closing in 10-15 minutes and the kitchen was closed.
However I was able to place an order off the digital menu and they happily delivered it to me. They did start clearing people out though by 845 in earnest. Shame because next stop was the TK Lounge (which was a big step down) but would definitely return if it was during an open window