How can I convert this recipe if I'm using a 9 inch springform pan?

Have made this and it is a real treat!
The 9" diameter pan is about 1/4 larger in area than the specified 8" pan.
Possible adjustments:
1) Make the same recipe, but it will be thinner (spread over greater area) and will probably cook faster, so check sooner for doneness. Add some ice cream or whipped cream at table as garnish, to make it go further.
2) Make 1.25X the original recipe and cook for same time.
3) Check the article referenced in the headnote, and the reactions of members here for others who may have encountered and solved a similar problem using a different-sized pan.