Check out this page:
https://wiki.asterisk.org/wiki/display/AST/Custom+Dynamic+Features
Adapting the techniques from the above link to FreePBX, add the following to /etc/asterisk/globals_custom.conf
DYNAMIC_FEATURES = ${DYNAMIC_FEATURES}#playmonkeys
and the following goes in features_applicationmap_custom.conf
playmonkeys => #9,peer,Playback,tt-monkeys
Do a core reload, and now the in-call feature code #9 will play the recording. The rest is left as an exercise for the reader.