The tween wasn't working correctly using your code. I fixed that by putting the tween binding, inside the click event. Note that this is not really a good solution, now a new tween gets added on every click. At least it got it quickly working for me...
Actually to answer your question, the changed value of the shape does not get visually updated. You have to call the draw function itself on shape, layer, stage (any container) of itself and it's children which you want redrawn.
I think changing your if statement in the updateCircle
function to the following should do it:
if (group.attrs.id == window.SelectedObjId){
group.setX(x);
group.setY(y);
layer.draw();
}
Furthermore, assigning properties to the global window
object is a bad practise (the selected group in your case). In the outer scope, I create a variable selectedGroup, which get assigned also during the click event. This variable is then used in the keyup event to check what group needs to be changed from position.
See also the fiddle for a working example: http://jsfiddle.net/BsK7Q/
Mind you, there still seem to be a few checks you need to, such as checking if it is a real number.