I had a 2x9 running XTR m960 derailleur and for chits and giggles tried to go 1x9 and dropping the chain was an issue, which I fully expected but figured I'd try it out.

As of a week ago I went to 1x10 with XT der with the clutch and I'm loving the change. NO chain drop, no chain slap and the list goes on.

Was a nice upgrade that myself and the bike needed.