Use a JDBC URL like jdbc:hsqldb:hsql://localhost:9010/play, as determined by the settings in your server.properties file. If you want a command-line tool, then I recommend SqlTool, as documented in the HSQLDB User Guide.

Use DBI/DBD::JDBC according to the POD/man-page documentation, except in place of a JDBC url, use a HSQLDB BER resource locator beginning with ber:hsqldb:, like

    dbi:JDBC:hostname=localhost:9111;url=ber:hsqldb:play

The connect string must consist of ber:hsldb: + the dbname specified in your berserver.properties file. For the sample configuration, the berserver.properties file contains the line

    server.dbname.0     play