Virgin Query

I have a small issue..
I was going to book a DJ flight from CBR-SYD for next Thursday, the 10am service. I have noticed that they have been cancelling many CBR-SYD flights over the last few weeks. Reasons?? Empty?? I will be at the airport at 8.30am, so if they cancel my 10am flight, presuming the 9am service to Sydney isn't full, could they just put me on this?

Otherwise I will pay the extra $50 and fly QF...