2009 Saturn VUE Whirring Noise

I hear a “whirring” noise that increases in pitch and frequency as I accelerate (and reduces when I decelerate). It is usually worse when the car hasn’t been driven for a while (e.g., in the morning). It is definitely rotational related. I have researched a bit and the three possible answers I’ve found are 1) tires, 2) wheel bearing, and 3) brakes. I’ve had it checked twice and both times, the tech said that he couldn’t reproduce it. I think that’s because they drive it on the highway and the noise is drowned out as you get to higher speeds. The best way to hear it is when you decelerate and stop. When you do this, the background noise diminshes and you can easily hear the sound. I’ve had the tech check the obvious and they say that it couldn’t be a bearing because the noise is very loud and distinctive. It is still under warranty (it has about 21K on it) and I don’t want to wait until something really brakes. The car (other than the noise) drives fine. I haven’t noticed any difference when you turn which (I’m told) is a key indication of wheel bearing issues, but I may just be having trouble hearing it. One other alternative is that it’s a “normal” noise, but that would be disappointing and annoying!