Powering with a 3S LiPo

I'm designing a project that needs to control 2 solenoids with MOSFETs off 12v. I'm using a 3S LiPo battery and I was wondering if I can use it to power the Arduino itself to avoid needing to work in the L7809 I picked up. The board I will be using is a knockoff arduino nano clone.

It is more efficient to use 12V to 5V dc-dc Buck converter since you are using battery.

I frequently use something like this inexpensive regulator.