Definitely not SACD--that requires a separate laser, and there is currently no universally accepted DAC interface to get a digital signal into the DAC. With DVD-A, I'm not sure if your Pioneer can read and, by itself, decode the disc, but my understanding, at least at this point, is that the software itself will not allow a 24/96 digital signal to be output from its digital output (one of my pet peeves with the medium), so an external DAC would not get a true 24/96 signal.
Dumb Question
Are the physical formats of SACD and DVD Audio different than CD or DVD? The reason I'm asking is that I have a Pioneer 525 DVD player. This only supports DVD and CD playback out of the box. If I hook up an external DAC which can decode the formats, would I be able to use this to play SACD and DVD Audio?