Alright so, It is correct that if you have lived in another country for more than a year you can get your file processed from the VISA office responsible for that country meaning if you want and if you request only then your file will be transfered from Islamabad to Abu Dhabi after December(since thats when your one year completes). Now why would you want to do that? Your process has started about 9 months ago and once your file is transfered to Abu Dhabi it would start from scratch and will take closer to 27 months so I don't think thats a good idea. However, changing the address to receive correspondence in Oman from Pakistan is totally up to you, if you feel that some one back home in pakistan can do that for you I don't see a point of that either but if you feel confortable changing your address form pakistan to Oman so you receive request letters in your hands then you can request for an address change and that would only change the address for request letter and your file would still be getting processed in Islamabad.
Regarding documents: A few applicants from Sept/October 2010 have started to receive rePCC and Imm forms request already so I think you will hear something very soon, don't send anything voluntarily at this point just wait for the requet letter and later you can send everything together including evidence and supporting documents for your case along with PCC and IMM forms. You will also need to include PCC from Oman since you have been there for 9 months.