Not wanting to let a cult move in to occupy it (9)
I believe the answer is:
reluctant
'not wanting to let a' is the definition.
I can't tell whether this defines the answer.
'cult move in to occupy it' is the wordplay.
'move' is an anagram indicator.
'in' means one lot of letters goes inside another.
'to occupy' becomes 'rean' (I can't justify this - if you can you should believe this answer much more).
'it' becomes ''t' (abbreviation. e.g. in 'tis).
'cult' anagrammed gives 'luct'.
'luct' put into 'rean' is 'reluctan'.
'reluctan'+'t'='RELUCTANT'
Can you help me to learn more?
(Other definitions for reluctant that I've seen before include "Loth" , "Hesitant, disinclined" , "Indisposed" , "Kenneth Grahame's dragon was" , "Disinclined to become involved" .)