I wouldn't recommend upgrading switches just to get 9216 MTU support unless you have a specific requirement for 9216. (Interested to hear BTW).
If I am correct in assuming the reason for this is to improve performance for things like vMotion and IP Storage, then I would recommend you review the two below example architectural decisions I have written so you can understand the pros and cons of Jumbo (if you dont already).
The same decisions also apply to vMotion traffic.
Hope that helps save you some money you can invest in other areas of your infrastructure.