8 /telepathy or non-verbal talk here/
The 8 / code is used in any client that does not allow things such as "/where you you going?/" because "/where" is not a command.
Code 9
Code 9 is used to change topic when a parent enters. Usage is generally "9 [new topic]" because the previous conversation may have been frowned upon. There is no set 'they left' code known.