Hello Marcos,
I have tested with last version of HikariCP, same issue. It seem the issue comme from the "connectionTestQuery" setting. By default it was set to "null" (reference.conf from Play) but it seem Play don't use JDBC4; so HikariCP throw an I/O exception. I set the setting to "SELECT 1" and everything run well.
extract from HikariCP documentation
If your driver supports JDBC4 we strongly recommend not setting this property. This is for "legacy" drivers that do not support the JDBC4 Connection.isValid() API. This is the query that will be executed just before a connection is given to you from the pool to validate that the connection to the database is still alive. Again, try running the pool without this property, HikariCP will log an error if your driver is not JDBC4 compliant to let you know. Default: none