You have to understand that 0900 Z is Zulu time (aka GMT), which the military uses exclusively. So while an exercise might start at 0900 Z, that would be 0400 CDT (local time), so in short, unless you were up at 4am to listen to this event, you missed it.
For help dechipering time zones and such, visit this site:
timeanddate.com
You will find a list of time zones, live time, and conversion utilities to convert time zones to your local time zone.
Hope this helps you out some!