Happen to be right about anger following answer by Penny (9)
I believe the answer is:
transpire
'happen' is the definition.
(I've seen this before)
'right about anger following answer by penny' is the wordplay.
I cannot quite see how this works, but
'right' could be 'r' (common abbreviation) and 'r' is found in the answer.
'about' could be 're' (regarding) and 're' is present in the answer.
'answer' could be 'ans' (A common abbreviation) and 'ans' is found within the answer.
'penny' could be 'p' (short for pence) and 'p' is present in the answer.
The remaining letters 'ti' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
'to be' is the link.
Can you help me to learn more?
(Other definitions for transpire that I've seen before include "Lose water vapour" , "revealed" , "Happen[s]" , "Become known about terrapins" , "Prove to be so, happen" .)