The M9 is Louisville's pro maple series. Nothing too special about it, you can get the same wood quality from a small bat manufacturer for around $65-75.
As far as the $100+ price tag for a wood bat, blame SamBat and Wilson! When Wilson bought the small manufacturer a few years ago, the bats skyrocketed from $70 to around $130, apparently someone didn't understand the concept of bulk pricing and mass production for the "retail" market. Once competators realized what he was getting per bat, some manufacturers followed suit. On the other hand... there's that supply and demand thing.
One small company I can think of, raised their prices almost overnight for the same product that was $40 cheaper the night before.