My $0.02 is not so much that a bunch of standardizations and pop up errors are needed, as that is a turnoff to users and will likely not accomplish what you are seeking in many cases. Yeah maybe a couple, but that the backend database should clean up most of this itself! I completely agree with the comment of Hack G who said "most SQL platforms have this covered"...exactly.
The fact that a provider puts in MD, M.d, M.D. md etc. could be slightly controlled at front end but to be honest, I think you'd find in user acceptance testing that you will have a mess there. If you put a message like "please use proper format" what is that? Is it M.D. or M.D or MD? Just clean up this on backend. Credentials, address, phone, name and license number (based on state) can all be done on backend or with a little validation. State license can say something like ("please use #####-## format for this state") Other stuff probably skip the validation.
Cleaning up on backend only affects performance if the entry table is the same as the table used to store and query the data...which isn't the case now.
Again, for us, the above is based on experience. We normalize the NPPES file and do all of the above using MySQL and it's not a super heavy lift.