If you have a Mac (or maybe on the web-based Cloud calendar) you can create a new event in iCal and set multiple alarms for a single event to trigger at a custom time. You could create an event for 9 PM, for example, and set two alarms, one for "9 hours before" and one for "at time of event."
Honestly I think it would be easier to create two separate events, but my example should work.