There is an issue in OracleBlobRDBMSMapping and OracleClobRDBMSMapping in the workaround implementation for OJDBC drivers < 10. If the jdbcMajorVersion is < 10, the code relies on some old implementation of the JDBC driver is called.
The i-net Oranxo driver uses a different JDBC major version being currently 3. This leads to a ClassCastException (com.inet.ora.ag cannot be cast to oracle.sql.CLOB) when writing CLOBs and an IllegalAccessError (tried to access class oracle.jdbc.driver.OracleResultSet from class org.datanucleus.store.rdbms.mapping.oracle.OracleBlobRDBMSMapping) when writing BLOBs.
The DatabaseMetaData:getJDBCMajorVersion() javadoc states "Retrieves the major JDBC version number for this driver" which in my opinion does not need to match the DB version.
I will add the patches I wrote that allow writing BLOBs and CLOBs using the i-net driver, I hope you can add these in the next release, that would be greatly appreciated.
Unfortunately I cannot provide access to the i-net driver, I hope you can somehow get access to it so you can run my test case.