The sync clock for digital isn't the same as the syncing to movie's 29 frames per second or TV's frame rates together such that the sound and visuals are synced. That is called SMPTE timecode. When digital audio came to being in the mid 70's and one of the big issues with any digital signals is a when you try to mix two or more sources together - the summing together of digital signals is how to sync them together such that you don't get drop outs or aliasing issues. So a word clock was developed so that every pro digital equipment could follow one word clock. The easiest way to bypass that is to place it back to analog and re-sample the analog signal back to the digital domain. But if you want to keep it in the digital domain then work clock is the most preferred way. There are quite a few standards of digital audio - S/PDIF, AES/EBU, MADI ( subset of midi) ADAT and TDIF. They all use word clocks to sync thing together, but there must be only one word clock. Then there are units that will sync together digital signals from machines that don't have the capabilities to sync (or adjust their internal clocks) such that the signal will get reprocessed to sync into the main stream digital audio.
Home audio isn't as complicated, and for the most part isn't really needed. Your cd collection once placed into your PC will follow your PC word clock, or if any of your equipment has a word clock, it will convert it's clock over. Cd players that have word clocks are mostly masters. It gets quite expensive to have adjustable clocks on such devices - you need a fairly large buffer to hold the data before syncing. In the studio these days most of the work flow are on PCs, so you just download the data into the PC and away you go.
If you have a good CD collection, it's just better to download the data into a dedicated PC and play from there. Far better that any CD player on the market that I know of.