Yes, you can install an operating system on each drive and select which one to start from.
Yes, you can install an operating system on each drive and select which one to start from.
Imagine a setup where Windows 8.1 runs on an HDD while someone tries to dual boot with Windows 7 from an SSD. You’d likely need both operating systems on the same drive to choose which one to boot from, unless special tools allow switching between them.
It seems like you're suggesting a quick start from one device and then switching to another, or experiencing initial difficulties when powering it on.