Advice from above - go to airport today if you can
For those in HKG , kaka has solid advice above: go to the airport early today if possible. Flights were zeroed out to accommodate.
For those outside HKG, I don't think anything is a "safe" strategy. This is possibly the biggest storm to hit HKG in what, 30+ years? It definitely will be HKIAs biggest typhoon ever. Keep trying to reach CX on the phone or via some method (maybe your outport in person) . As you see from anecdotes above, when you can get through they seem to be doing a good job, like the guy who was put on BR LAX to TPE. But you need to speak to someone.
Predicting how things will play out post typhoon is very hard. Everyone is crossing their fingers HKG doesn't have flooding or serious damage, so normal ops can get back underway Monday night / Tuesday morning.