The existing 0.3.x series of the Python client library is now closed for feature requests.
For the upcoming 0.4.x version series of the client library, we are transitioning away from SQLAlchemy in favor of direct connectivity with asyncpg (for PostgreSQL), aiomysql (for MySQL) and pyodbc (for Microsoft SQL Server). In this new setup, we have more control over how the connection is established, and we can incorporate a pre-created SSLContext, and pass that as the ssl parameter of aiomysql.connect.
Many of the dependencies for the upcoming version are already open-source and available on GitHub, e.g. json_strong_typing (which helps us synthesize Python classes from JSON schema) or pysqlsync (which helps us synchronize schema and data with a database server). We have been planning on making the new version of the Python client library available on GitHub as well (once it's ready) but we don't have a date yet.