http://forum.hibernate.org/viewtopic.php?t=935274&highlight=multiple

I stumbled over this in the message boards.  We did the same thing a 
couple of weeks ago.  Download the Oracle 10g driver (from the Oracle 
site) and use that instead of building these adapters.  It does work 
with 9i databases and functions over the 4k barrier (we tested up to 
50k).  This is MUCH simpler than trying most of these other solutions 
since all you need is an updated classes12.jar file.

Not sure if both of these were needed, but we also add the following 
in the hibernate.cfg.xml:

        <property name="SetBigStringTryClob">true</property>
        <property name="batch_size">0</property>

I still can't figure out why Oracle never fixed the 9i driver, but as 
long as the 10g driver works I'll take it. :)