You say 9 hours is decent. It could be, the problem is this is advertised play time, which is rarely achieved. It's like car mileage, yes in theory you could get mileage printed on the sticker, but in real life it does not work.
You will not get 9 hours because that is the time when using the player with minimal features, the minute you start going for higher rate output or with additional features - that time will not be possible. Plus battery will deteriorate with time and you will be getting less and less with each charge.
Realistically you will be getting more like 4-5 hours playtime out of this DAP when new and likely just couple hours after several months of use, which is a shame in a $1300 device.