Guvnor,
I would imagine that the 9-day duration of the sale is because nobody is flying at the moment and they need money right now, today and not some time next month. They don't want people thinking about it for a few weeks. They need to fill seats and earn money NOW.
Theres nothing to stop them from extending this sale if it proves successful. And considering that I'm finding it difficult even to get onto their website, it seems to be working.
Regards,
V.