Genoise cake conversion

Hi,


I have made Alice Medrich's Strawberry Celebration Cake (chocolate Genoise) from her book "Bittersweet" twice with great success. However, the recipe is for an eight-inch cake and I need to make a nine-inch cake. Reading a 2011 post on this site where a reader wanted to know about using 9" pans for a cheesecake recipe that calls for 8" pans, in one answer you suggested that the bake should increase the recipe by 25% and in a further post, an increase of 21% is suggested.
Any help or suggestions you offer will be appreciated,


Please help.

I didn't find the right solution from the Internet.

References:
 www.thefreshloaf.com/node/51245/genoise-cake-conversion
Kitchen Equipment Video


Thanks