it's more important for organisation in which developer works or for developer ?
is developer's certificate with note "OPN Certified Specialist" move with him? or stay in organisation in which hi worked ?
The "OPN Certified Specialist" designation is definitely of more use to the organization for which the developer works. I would never put the 'CS' titles on my resume for example. I would instead use the other title. For example, passing 1Z0-515 earns you the Oracle Data Warehousing 11g Certified Implementation Specialist designation and you also become an OPN Certified Specialist. The first title is what I consider useful to me.
That said, I am reasonably confident that the CS designations follow the developer. First, because it makes no sense otherwise. The reason Oracle made the program was to reward companies that had a certain number of people employed that were trained in various technologies. If the specialist 'count' stayed with the company when the certified employees left, then this would be pointless. Second, when I badged to my current employer, certifications that I had earned previously that were part of the Certified Specialist program were applied to the company I badged to.
This is correct - the certification goes with the individual. However, the only way this additional designation is helpful to you is in looking for a job. It is something that you bring to the table if you are seeing a job with an Oracle Partner. Your OPN OCS certification will count toward the partner level of any new Oracle Partner who employees you and be removed from the credit of the Oracle Partner you left. If you are working for yourself, or for a company that is not an Oracle Partner, this designation does not hold much value, but it does travel with you and does not remain with the company you left.