Can a neighbour with a bluetooth headset hear my TV's bluetooth
emission through a wooden wall?
If you're asking about if the signal can get through, then the answer is yes. To block a bluetooth signal you'd need very thick and dense walls (something like thick concrete walls) or something that acts as a Faraday cage.
Usually bluetooth transmissions are encrypted by default, the security on this mainly relies on the pairing method.
But as forest commented, you shouldn't be worried about anything. Statistically speaking I think that it's quite unlikely that your neighbour would have the cryptographic expertise to hear your transmissions.