Restrained about petition by credit centre (9)
I believe the answer is:
repressed
'restrained' is the definition.
(thesaurus)
'about petition by credit centre' is the wordplay.
I cannot really understand how this works, but
'about' could be 're' (regarding) and 're' is found in the answer.
The remaining letters 'pressed' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for repressed that I've seen before include "Kept under control; put down" , "Kept bottled up" , "deleted recordings sometimes were" , "Pent up" , "Checked" .)