The requirements for 2.00 are the same. But if you're using source code version (what to edit source code), then you also need MVC 3.0 installed (or VS 2010 SP1 which is already shipped with MVC 3.0)
I have 1.9 running on server. If I install 2.0, do I need to install anything (like mvc) or no ?
Is requirement for 2.0 is same as 1.9 for server ?
Most likely you will need all the latest technologies for .NET and SQL Server. Find a website hosting provider that stays up-to-date on all of Microsoft's technical-software releases and you will be fine.