Yes every rumour mill repeats it, but the first one is over a year away.
If there are more than eight aircraft then they will have no trouble committing contractually to give Perth airport certainty committing the capital required. Sadly rumour and 'could' isn't factual it is hearsay and Perth airport rightly called it.
As to the more aircraft you may want to have a close look at their gearing and off balance sheet debt before listening to rumours.