Position object in Scene Editor in Xcode 9 beta
As orangenkopf quoted, My problem was with the model size. It was huge and hence didn't get rendered properly. When i change the scale of the object in Xcode Scene editor to a minimum value, i am able to view the object correctly and place it anywhere needed.
The best way is adding .dae file into the project and then Editor -> convert to SceneKit scene file format (.scn).