Pulling out the phone number (9)
I believe the answer is:
extension
'phone number' is the definition.
'extension' can be an answer for 'phone' (thesaurus). I am not sure about the 'number' bit.
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for extension that I've seen before include "Office phone, perhaps" , "Another phone" , "Additional time for repayment" , "telephone number" , "supplement" .)