What exactly do you mean by this question?
(1) is the office physically open as in, can I visit it and ask questions? No, the office is never open to the public. IRCC does not offer walk-in or appointment service for visa officers.
(2) is the office open so I can send an outland family sponsorship application? The office was never fully closed for this purpose. People have been sending applications during the pandemic.
(3) is the office open for biometrics? Biometrics appointments will be handled online when fully available and you'll be able to go to a Service Canada office to do the biometrics.
But in general, even when fully open, the Sydney, NS Case Processing Centre is not open to the public.