Where are you? Zone 9 California tells us almost nothing. Give us a zip code

95670 -- Hot dry summers, winters rarely dipping below 30 degrees.

Much hotter than what I'm familiar with, so I don't have direct knowledge. What I know is what I've learned through reading while coming up with a mixture of grasses in the desert here.

The only grass that I know of that's native to that area is blue grama. It's a very attractive grass, but it's a bunch grass, so you'd probably need to overseed periodically unless you don't mind a slightly untamed look. If you were at a higher elevation, you might see it spread a little, but it's likely to be a bunch grass where you are. Mowing may help it tiller a bit. On the flip side, if it doesn't get too tall there, you might be able to let it go to seed.

Buffalo grass isn't native there, but UC Verde was developed by the UC Riverside and UC Davis andI think it would do well where you are.

Buffalo grass and blue grama are often planted together in a lawn setting.

They may need a little irrigation in the hottest part of the summer to stay green, but they'll live with no additional water even if they do go dormant for part of the summer. But it would only take about 1/2 inch of additional water per month to ensure they stay green.