scaling up a Frittata from a recipe

I am cooking a recipe today from the Smitten Kitchen cookbook. It is a feta/bacon/potato frittata. I am bringing it to a potluck gathering later today for people who enjoy exploring new cookbooks.

It is my first frittata, and my first major recipe using my newish cast iron Lodge 10SK pan. I have seasoned it multiple times with bacon fat and then baked/cooled it as per posts on this site.

So, I see that the frittata recipe is actually for a 9" cast iron pan. I know I am being paranoid, but as I tend to always have at least one screw up per new recipe I thought I would come to you guys for advice first.

Do you recommend I use the ingredients as per the recipe and watch it carefully since it may cook quicker, or scale up the ingredients slightly? Any pointers on what to look for to say the frittata is done, as this is my first one?

Thanks folks.