Means of support: concerned with where they come from (9)
I believe the answer is:
resources
'means of support' is the definition.
(resources might support someone)
'concerned with where they come from' is the wordplay.
I cannot quite see how this works, but
'from' could be 'o' (I've seen this in other clues) and 'o' is present in the answer.
'concerned with' could be 're' (re can mean regarding or about) and 're' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for resources that I've seen before include "Available reserve supplies" , "Personal attributes" , "Useful materials, assets" , "country's means of defence" , "Teaching materials" .)