@ANGRYBIRDSFILMSALT This can either be simple or complex depending on the path of your object.
Assuming it is a straight path, you can use an Empty Object for it. Make the anchor of the object to be 50, 0 so the bottom center of the object will be used in transformations.
Calculate the distance from point A to point B.
Calculate the direction from point A to point B.
Now move the empty object to point A.
Rotate the object to the direction given in step 2.
Now rescale the object so that the y matches the distance given in step 1. You can change x to any width you like - this will be the stroke length.
Now you should have a line connecting from point A to point B.
You can use this every time an object is moving to a point. However, do note that distance is affected by the zoom; it'll be normal at 100% zoom but it will double when zoom is 50%.