It's not impossible to code your own private server. But it has been tried, and failed. It's so much work and it would take a full, experienced, and dedicated team to pull off. That is not to say, that you'd be able to make a fully featured server. It'd probably be the biggest and worthless piece of **** for a long time.
The other option is to try buying the server files. Chances are, it's more expensive than you could afford. Given the thought they even bothered considering such a request, which is doubtful.
And the most likely option is, someone internally leaks the files or someones gains access to the files and steals them. It is your most hopeful chance of getting a 9dragons server. It happens all the time, Perfect World anyone?
Anyway, no you cannot play 9Dragons in offline or single player mode. And practically no on a 9dragons private server.