I always found SHimano chains run quieter on Shimano cassettes.
Beware, though - 9000 km is a goddamn long life for a chain, and if the chain was more worn than you thought, it might not mesh well with the cogs and chainrings that have worn to match the old chain. Specifically, the chain is liable to skip on the cassette under load, or be very noisy on the chainrings.