I have not seen any extension but you can make your own userscript to redirect any time your browser hits Google Docs homepage
// ==UserScript==
// @name Google Docs Set Homepage as Starred
// @description Redirects the homepage to the Starred page
// @include https://docs.google.com/
// @include https://docs.google.com/#home
// @exclude https://docs.google.com/#starred
// @run-at document-start
// ==/UserScript==
location.href= "https://docs.google.com/#starred"
Save as whateverfilename.user.js and let your browser install it
I didn't include the tab link on from the Google bar on top.
https://docs.google.com/?tab=oo&authuser=0#home