Okay, all you RMAN experts out there!

I have an 8.1.7 database that I'm backing up to Disk using RMAN.
I want to create a duplicate of that database on a DIFFERENT machine. I want the duplicate to run a test upgrade to 9i.

The catches are:
The 8.1.7 db is 32 bit on AIX 4.3.3
The new box is AIX 5.2, and only has Oracle 9i, which is 64 bit.

So, can I create the duplicate even if 8i isn't on the new box? Are the word differences going to cause me a problem?

Thanks a bunch!