California is a big place. Even zone 9 in California is a big place. Can you please be more specific about where you live? If you live in the southern part of zone 9 or in the Central Valley, then St Augustine might be the best, but it does not come as seed. If you live north of Santa Barbara or west of the coastal range, then fescue seed would be better. if you already have fescue or Kentucky bluegrass, then fescue. If you already have bermuda, then St Augustine.

Sorry -

I live in warm San Jose. I was thinking about dwarf fescue but can it tolerate 50% shade in the summer?

I don't have much bermuda thank goodness. Killed it off before I seeded 10 years ago.

Ginny

Marathon, Marathon II, or Marathon III should work in San Jose. They get dwarfier with higher numbers. Be sure you remember which one you used for future reseeding if necessary.

Are you out of danger for freezes for the rest of the year? If so get the seed down ASAP. The longer it grows before summer heat hits, the better. And the earlier you can get it sprouting before crabgrass season, the better. Crabgrass germinates in the spring which is the second reason to seed fescue in the fall.

Also do not expect fescue to spread and fill in thin areas. It's not that kind of grass. If you need to improve density, the only way is to reseed and preferably in the fall.

Thanks for your recommendation!
Ginny