Generally, no. Av mode meters for exposure and selects shutter speed/ISO based on the light and your settings, but image stabilization is not part of the exposure calculation. IS helps reduce blur from camera shake; it does not change the amount of light reaching the sensor.

That’s why the camera typically won’t assume it can use a slower shutter speed just because IS is available. It also can’t know whether your subject is moving, and a shutter speed that’s fine for a static scene may still blur people, animals, or action.

So yes, in some situations you may be able to get a cleaner image by manually choosing a slower shutter speed and lower ISO than the camera picked in Av, especially for still subjects. But that only works when subject motion isn’t the limiting factor.

A common guideline is the hand-holding limit of about 1/focal length, with IS sometimes letting you go several stops slower, depending on conditions.