- Is possible maintain a SQL application without a ORM? - (when *1 how to manage migrations? )

In clojure, it’s almost certainly preferred

For managing migrations, most prefer something like migratus or ragtime

There is some tool that helps to keep plumatic/schema or other schema tool in sync with SQL schema? Or "test" is the solution to find error's?

You could certainly write fns that would generate a plumatic/schema from a database schema, e.g. using DatabaseMetadata, or that would reconcile one against the other

So much depends on the particulars of your use case