I just migrated standalone 9i to RAC 10g 130 Gig database using exp/imp in 14 hours, end to end.

Having your RAC environment already created...

1- Export/Gzip (on-the-fly) full, rows=n 9i database
2- Export/Gzip (on-the-fly) operational schema, rows=y
3- FTP *.gz files
4- Import/Gunzip (on-the-fly) FULL dump
5- Disable 10g constraints in operational schema
6- Import/Gunzip (on-the-fly) operational schema, skip=y
7- Gather fresh stats