It takes Light 8.3 minutes to reach the Earth. If Gravity travels as slow as Light, then it takes 8.3 minutes for Gravity to reach the Earth.
The Gravity wave is going to pull the Earth towards the center of where the Sun was when the Gravity wave left the Sun.
If that was 8.3 minutes ago, then the Earth will be orbiting, at any given moment, around a center point that is 78 thousand miles away from where the Sun is at the present if Gravity really is as slow as Light (because that's how far the Sun will have traveled in those 8.3 minutes). Gravity and the Earth aren't predicting the *future*, after all, but rather reacting to current and past events.
And yes, the Earth is *also* traveling those same 78,000 miles in those 8.3 minutes, but the angle of the plane of the Earth's orbit is still going to be centered on where the Sun was when Gravity left it.
And this angle will be different (perhaps only slightly, perhaps by a large amount, depending upon the speed of Graivty) the further a planet resides from the Sun.
Where to start. Hmmmm.....Here is a really good explanation:
http://zebu.uoregon.edu/~imamura/talks/gravity_waves/gw_intro.html