you will be fine. these things don't hit earlier than planned, it's usually just the intensity and whatnot.

HK Observatory has instructed people that they "may" raise the T8 signal at 6pm. This pretty much means there's no way it's going up before then. And it means the storm, if it hits as predicted, will be intense late night.

Anyway, the key with these things is not being on a cancelled flight (as some unfortunate posters above have already experienced). But if you're actually on a flight that's going, the airport and CX are pretty much pros at handling the situation. They only briefly shut down operations IME even if you're in the thick of the typhoon, which again won't happen until 10pm or later tonight if it occurs. The key is not being on one of the proactively cancelled flights, or less-likely but also happens when you get a diversion. In these situations you can be sol for 24-48 hours.

There's no way they'd can CX882 (same with CX840, etc.), because it'd be unnecessary and would also cause extra havoc for the return flights. They already have enough problems on their hands.