It may be substantially demagnetized. Do you have another Tele? If so, take a small Allen wrench and gently stick it to the neck pickup of the other ("good") Tele. Take note of how well the magnets attract the wrench.
Now try the same thing with the sick pickup. Does it feet the same? If the magnetic pull is weaker, that is the problem. If not, it could be a poor solder joint in the circuit, or some other goofiness perpetrated by a previous owner.
Some pickups can sound really anemic when a the wire is broken in the coil. This is referred to as a "zombie" pickup because the DCR will be infinite on a meter (open circuit)--but the pickup still makes some sound due to inductance produced by the thousands of turns on the coil. We know this is not the case with your pickup because you got a 9K reading by testing it directly.
First, the neck pup on a Tele often does sound compressed and a bit warm. But 9k would be an awful hot pickup for the neck for sure.
I would look inside at what pickup it is, the wiring etc first thing.