I've looked around but can't seem to find one. Does anyone know when the dvd will be released in the US?
I don't know about an international release, but the movie will be released in Japan on September 26th or 27th, 2017. CDJapan has both the Japanese DVD and Blu-ray versions available for pre-order now. The Japanese copies have been confirmed to have English subtitles.
Aniplex of America has announced Ordinal Scale for December 19th. (The details are roughly halfway down the page.)