Bust? Very rude about that! (9)
I believe the answer is:
insolvent
'bust?' is the definition.
(I've seen this before)
'very rude about that' is the wordplay.
'very' becomes 'v' (abbreviation).
'rude' becomes 'insolent' (I've seen this in other clues).
'about that' is an insertion indicator.
'v' going into 'insolent' is 'INSOLVENT'.
(Other definitions for insolvent that I've seen before include "In the red" , "Broke" , "gone to the wall" , "deep in debt?" , "on the rocks" .)