Can we calculate coordinates/points using center point and drivetime using Google API to create a polygon?

I am trying to create a polygon using Google APIs. Now, I know how to create a Polygon using Google Maps. The issue is with the points. 

Earlier I was using a third-party service: Smappen to get points for the isochrone using center point (lat, lng), mode, and drivetime which I then passed to google maps Polygon to create the Polygon. But, that third-party service returns 429 Errors if there are a bit too many requests.

Now, I would like to do that using Google API if possible. I tried their docs already but any API that relates to polygon requires coordinates to produce Polygon like Rectangle, Triangle but I didn't find any that matches my scenario that is producing those coordinates before passing it onto google maps Polygon to create one. I also check other posts that only show third-party services to do it.

Can someone guide me if this is possible?