No, that shouldn't influence the sound at all. Opamps and buffers only know the absolute difference between the supply rails (they have no idea where the ground really is), and as long as the output is not too close to the supply voltage, it should all be fine. And you really don't want the output to be anywhere close to 9V.
Besides, the difference in 0.03V truly is negligible. Your parts probably have worse matching than that.