for upgrade if you want to use ILM, I don't think so it will help you. Upgrade process most of the time works on all of the data in tables. ILM only proposes to move old data to cheaper storage. There are few steps where you can reduce the upgrade time by processing data for last few periods. ( Please raise SR with Oracle regarding this).
to reduce the data I think purging and archiving is required
For upgrade we want to archive/purge some part of the data (May be upto 2009 period). And rest we can upgrade. So for this case, can we use ILM?
Also, using archive and purge, there is no way we can do archive using regular archive/ purge methods for certain modules, for example AR.
So can we achieve that using ILM?