We are now opening the 64-bit VfW codec for public testing. This requires a 64-bit OS and a 64-bit Vegas 9 install. It is also recommended that you update one Vegas component to help with smooth playback at sub-resolutions (see the knowledgebase.)
That build will become official maybe later today -- so download and install without concern that it will be revised in the next day or so. For those using HD/4K versions will be out at the same time. The HD/4K tools contain First Light that will be AJA and Blackmagic enabled for RT color correction out to an external displays and other nice tweaks.