Kept quiet, being shy (9)
I believe the answer is:
preserved
'kept' is the definition.
(preserving is a kind of keeping)
'quiet being shy' is the wordplay.
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'being shy' becomes 'reserved' (reserved can mean shy or timid).
'p'+'reserved'='PRESERVED'
(Other definitions for preserved that I've seen before include "Kept in an unaltered condition" , "Maintained in an unaltered condition" , "Kept safe from harm" , "Prevented from decay" , "Prevented from decaying or spoiling" .)