pt-table-sync: syncing slave from master that has different credentials?
Yes you can do that, there are switches for the CLI so these will hopefully get you correct access to the slave... 

--slave-user and --slave-password 

Here is a link to the specific part of the documentation that provides this information 

https://www.percona.com/doc/percona-toolkit/LATEST/pt-table-sync.html#cmdoption-pt-table-sync-slave-user

Please note at the top of that page:


  This tool changes data, so for maximum safety, you should back up your data before using it.


Disclosure: I work for Percona