If you have a DC in of 8.5V will a DC out of 19.5V work without ruining it?
I would not recommend this. Whenever you have device from a manufacture that states the required voltage (especially when you don't have a schematic to understand why that's the required voltage), it's best to stick with that voltage input so you don't risk damaging your system. If you did stick 19.5V into the system, best case scenario is that the system works just fine. Worst case is you start to see the magic smoke and it gets damaged.