Tube output stage CD player ?

I'm not particularly technical, but the common meaning is that a CD player which uses tubes in its analog stage would be considered a tube CD player.

Tubes are used in the output stage.

The output stage on a DAC / CD player is similar to a phono stage for a cartridge. So a tube cd player uses tube(s) to amplify the signal to line level.

Which one sounds better?

That one has been and will continue to be debated on this site forever with respect to amplifiers, preamps and the like. Were you to ask the designer of a tubed unit, doubtless he would say the tubed one; likewise, the designers of the Levinson and similar players would say solid state. And while I prefer my tubed dac, I'd be the last one to assert that an Ah! Tjoob CD player sounds remotely as good as an Accuphase. Ultimately the one that sounds "better" is the one you think sounds better after careful listening, I guess.