Obtaining a visa within 8 days from application is feasible, just matter of luck and lack of applicants before yours is processed.
The only hitch that I see is the waiting time for the Marriage Certificate to be returned from the NSO.
If you don't follow up it can take a life time.
We waited 4 months just for that, our misfortune was that lots of government employees were drafted in to help for the Elections, and lots of public buildings were turned into polling stations.
Good luck