CDS is jin's crouch demon stance, is done by doing B1, and he enters a particular stance since T5, and has been improving ever since, in TTT2 they gave another stance called Zenchin, which is called "Zen" now, the effects are the same as CDS, the only difference is that CDS has more crushing proprieties compared to Zen which moves him forward while cds moves him backwards.
As for execution, Mishimas are execution heavy characters, whiff punishing with eletrics can be pretty difficult to achieve in high level matches due space control and clutch, in the heat of the match its really hard to find that opening, but its super doable, this is also what makes them super dificult to learn, since not only they rely on this move a lot, wavedashes and other options out of it are extremely required to know alternate ways to access them.
Kazuya is a high execution character from the ground up: he relies mostly on his eletric to do anything, to attack, to apply pressure to create most of his frame traps, to whiff punish, to be safe, and he has one of the harders CH just frame launchers in the game.
While Jin is not as heavy as Kazuya in T7 he is going to be a bit more dificult since his regular WHF never launches, technically you will have to learn the just frame version to use it all the time.
If you haven't watch the dublin qualifiers, just check "datguyoverdur" he was playing DVJ on a d-pad and was doing fine, but in top 8 he knew he was fucked since it would require far more than what he was doing to mantain a good threat ratio using Devil Jin, since he knew he couldn't deliver, he switched to a easy character, even if Devil Jin is one of the most strongest characters in T7.
Things he knew he was't ready for:
whiff punishing with EWGF constantly (this is a must with any mishima)
EWGF off ws2 and hellsweeps up close (more damage)
side step eletrics
double eletrics combos (do more damage)
Wavedash into B4/hellsweep 50-50s (he wasn't ready)