HEVC Main10 hardware decoding has been available since 2015 with Maxwell GM206 and carried over to GF10 series GPU using Microsoft DXVA2 API and software player like MPC-HC, what is new is HEVC Main12 hardware decoding which Pascal GPUs supports. VP9 hardware decoding is the same also, using DXVA2 API & MPC-HC you have it for a while now.
But Video Codec SDK 8.0 has not been release yet, so you can't do 12bit hardware decoding until then. Microsoft has not release new DXVA2 API documentation or support for 12bit hardware decoding, so you can't use it with standard DXVA2 API for now.