I personally would wait for it to be fully released. People pre-ordering their N9 when nokia decides to bail it out (like they did with N950) and uses the its hardware for W9 (or sea ray) will be pissed off . In other words don't invest on something which may later become vapourware.

Also there were initial problems with N900. I do not know if the same sort of ordeal would happen with N9. Waiting here might give you more awareness of any potential shortcomings in the said device. nokia may or may not release fixes for any hardware shortfalls on N9. If they do and you happen to get it later than having it preordered, chances are you may not suffer any shortfalls unlike the first adopters.

Just my 0.02