Think nostalgically about car having small coupé's shell (9)
I believe the answer is:
reminisce
'think nostalgically' is the definition.
(to reminisce is to think about the past)
'car having small coupe's shell' is the wordplay.
'car' becomes 'res' (I can't justify this - if you can you should believe this answer much more).
'having' is an insertion indicator.
'small' becomes 'mini' (short for miniature).
'shell' says to hollow out the word (remove centre letters) (only the shell of the word is left).
'coupe' with its middle removed is 'ce'.
'res' placed around 'mini' is 'reminis'.
'reminis'+'ce'='REMINISCE'
'about' is the link.
(Other definitions for reminisce that I've seen before include "Say what one remembers" , "Remember past" , "Cast mind back over old times" , "reflect" , "Recount memories" .)