the clutch release bearing only rotates when
the clutch is pressed down. while the foot is off it it is away from the clutch cover and fixed to the gearbox, so not turning so can't make a whining noise. as long as it's not dragging against the cover forks.
when you press the clutch it releases the gearbox from drive from the flywheel/engine so thus stops turning, while parked anyway.
does it make the noise whilst parked?
there are other things, thrust bearings on the crank for instance.
the maserati 3200GT aparently suffers from weak thrust bearings on manual gerabox cars. what happens is this,
jump in car in the morning,
press clutch down so engine can turn easier for starting,
force of clutch releasing presses crankshaft against the thrust bearing faces,
due to starting like that with little lubrication until the engine actually starts the thrust bearings wear very quickly.
must admit it's not something i'd ever thought about before reading that a few years ago, i'd always pressed the clutch to "help" the starter, probably still do tbh
so to sum up i would say that if whilst car is parked,
foot off clutch pedal gives noise, pedal pressed down and then noise stops. that would point towards being a noisy gearbox.
foot off clutch pedal and is quiet, press pedal and noise starts. that would be thrust bearing