Thanks to this forum, my first script !
Nate Lovell - (youtube.com/user/peregrinecommando99)
The script does the following in the following order:
1. Centers the anchor point of the layer
2. Gets the layer's width and height via sourceRectAtTime() method
3. Pre-comps the layer and sets the Pre-comp's dimension got from step 2
4. Centers anchor point of the child layer and centers it to screen
5. Sets position keyframes to the child layer to animate it from out of the screen to the center of the screen
6. Duration is converted to frames (commented currently)
Please have a look and suggest changes and point out mistakes.