The release of 0.9 brings several new features including expanded language features and improved tooling in Visual Studio. Soma Somasegar penned a post that you can read in full here and he states that the new langue service has been rewritten and the result was a dramatic improvement to interactive performance.
Microsoft states that a key piece of the TypeScript ecosystem is the development as an open source project on CodePlex. Currently, there are hundreds of developers engaging in the project to help define the direction of the platform.
While Microsoft has not issued any specifics on when TypeScript will hit the 1.0 release, they are committed to making it fast and flexible tool that is shaped by user feedback. Knowing this, if you have any feedback about the platform, make sure to let Microsoft know as they are listening closer to the developers’ requests.