Official here means the club over here paid their dues (as in membership fees etc etc) to be officially recognised by the FC as the supporters' club in Malaysia.  Normal practise is that they usually only approve 1 per country, so that the club that paid the fees will be given the priority over other clubs who are deemed to 'ride' with the popularity of the FC. 

Of course, there will be official clubs that will mis-use this privilege and start imposing themselves locally, normally without the knowledge of the FC themselves, as supporters' club are not governed by the FC themselves anyway.  I believe some other fan clubs in Malaysia are experiencing the same thing as well, being non-official as opposed to being officially recognised by the FC.

Pros and cons actually with the whole offcial supporters' club thing.