I'm guess "8" was a typo as it's the same key as "*".
Anyhow, to your question about order...
Order of almost all events matters. Stuff like aliases don't. On JOIN does matter, though. It matters because only the first matching one will trigger in a single script file.
For example, if you put on *:JOIN:*: { } before on *:JOIN:#chan1: { }, then the second one will not trigger because the first one matched.
