As far as I know creaking is not killable in Minecraft, but for some reason Warden can kill it, creaking can be killed only by breaking the creaky part.
MC-299376
Creaking
Resolved
Invalid
0
This isn’t a bug. The creaking isn’t getting killed by the warden. What has happened is that the warden has pushed the creaking far enough away from the creaking heart that it breaks.
You said:
Which is true however the creaking also despwans if it is: daytime, or it goes out of the range of the creaking heart (32 blocks i think)
So this is intended behaviour. The warden isn’t dealing damage and “killing” the creaking, instead it is knocking it back until it is out of range and despawns.