It depends on the brand. Hobbs wool and Quilter's Dream wool are preshrunk and treated so that you do not have to worry about batting shrinkage or bearding. Off-brands can act very differently. I'm not sure about QD batting, but Hobbs wool batting will shrink about 3% -- which is typical for most cotton battings too.
Not prewashing your fabric doesn't matter. What does matter is how much quilting you do. If you do a reasonable amount of quilting with lines no more than 3" or 4" apart, the fabric and batting are bonded together sufficiently that the batting will take control of shrinkage. If your quilting lines are far apart, say 10", then a fabric with an inclination to shrink more than 5% or more will be able to do that. When the fabric and batting are quilted reasonably well, they shrink together. Since the batting has more heft than the fabric, the batting ends up controlling how much everything shrinks.
Edit: If you want no shrinkage at all, use polyester batting. Polyester batting does not shrink.