As it depends on the scalability requirements for your DC, I would suggest to use the compare feature on this page:
https://www.cisco.com/c/en/us/products/switches/nexus-9000-series-switches/models-comparison.html
Nexus 9500 - EoR switches
Nexus 9300 - ToR switches
Recommended typologies and protocols for new designs:
- topology: CLOS (spine-leaf)
- protocols/solutions: VxLAN with MP-BGP EVPN & DCNM or, if you are looking for SDN solution in DC, ACI (Application Centric Infrastructure)
Stay safe,
Sergiu