Originally Posted by
bikeman715
........
2. for being a dura-age cassette you need a dura-age chain .
3. because the crank is a triple , you need a long cage derailleur so it can take up the chain stack when you riding in the small chainring .
ANY 9 speed chain will work!
Likely a short cage RDER will work, since the OP's chain wrap is only 32T.
A long cage may be a better choice if the OP plans on possibly using a larger biggest cog on the cassette though. That would allow "future expansion" for a 30+ T cassette.