OK, I checked the manual, and answered my own questions. It does 8 channels only in TDIF and ADAT when in 44.1 or 48Khz. The AUX digital outputs are mirroring the inputs, allowing you to send the inpiuts to another device. When your sample rate is higher, 88.2 and above, the AUX inputs are required to get more than 4 channels (up to 8) of high res digital. It uses a version of SMUX, call Bit Spliting, or BS for short (ha ha).
As for your original question, here's a part of the manual....
"7. Clock Section
The ADI-8 DS provides an outstanding clock section with professional features you won't find anywhere else. The unique Intelligent Clock Control (ICC) enables a flexible operation with internal clock (44.1 and 48 kHz, in DS mode 88.2 and 96 kHz), external word clock or the digital input signals. These options are easy to understand and easy to use thanks to a clear display of the corresponding lock and sync state.
A/D
The clock source of the AD-converter can be Internal (quartz crystal), External (BNC word clock). and Input (the digital input signal TDIF or ADAT).
D/A
The same options are available for the DA-converter.
The key DIGITAL INPUT determines the digital input being used, and the clock source in case INPUT was activated before."
So there you go. A resounding YES to your inquiry. Sounds like a nice interface.