I was earlier working with Directx 9 and Nvidia Physx based racing simulation game for a couple of years. 

Am now looking to develop a new version of a similar game but am open to exploring the latest technological SDK's for the graphic programming. 

Request guidance on which direction to explore. 

I think the best is what most of the industry is using. On PC, you can immediately jump into DirectX 11 and start writing rendering code. You can also start with DirectX 12 or Vulkan, but you will probably start with writing memory allocators and much boiler plate code before writing any rendering code. OpenGL also seems like a popular choice but less for professional development, more for tech demos, papers, courses, or at least it seems to me.

You will find tremendous learning material for any of those, especially for DX11.