Hello Network Digger,
I hope you are doing great,
Accoding to the following document the 3.X version should support the leaf:
- https://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/3-x/verified_scalabilty/b_Verified_Scalability_3_0_1x_and_13_0_1x.pdf
It seems odd, but if the leaf supports FCoE, it should work with no problems, the confusion might be that this C9396PX is EoL, and therefore is not shown in the link you provided, since it shows the current products that are supported and not EoL.
My recommendation would be to set up a window and test the config, and after it was successful, move it to production.
Keep us posted,
Please qualify all the helpful answers!
David Castro,