Hello carlosmp-SW2016,   You are correct, you won't need a license for OS9. You would want to install OS9 from scratch using ONIE.  
Hi - I was looking to get some S4048-ON to do some testing on.  I am a bit confused about the licensing on these switches.  Some say they only include ONIE, and some include OS9.  After a bit of research, it seems that OS9 can be installed without license, since it's included with the base switch.  OS10 is the one that has several options for the license (community or enterprise). Are our assumptions correct?  Want to make sure before we start doing some testing for an upcoming project. TIA, Carlos.
S4048-ON License Question