Think of it this way: A balloon is space and the speed of sound is the limit at which waves can travel across it. This normal for sound waves. If every bit of the balloon expanded at 1 inch per second, a small balloon would be getting bigger, but wouldn't exceed the speed of sound. A sound wave will outrace the expansion.
Once the balloon as expanded to about 2500 feet in diameter, the expansion along the balloon will be greater than the speed of sound. A sound wave will never make to the other side. That said, no one place is expanding more than 1 inch per second. Nothing in part violates the speed of sound.
But nothing can travel faster than the speed of light (no matter or energy or information), relative to the source point.