I use Suntour bar-end shifters (the classic ones with the silver body, black grip, and power ratchet mechanism) to shift 9-speed 11-34 cassettes for the past fifteen years or so. Works fine. I've used all manner of rear derailleurs with these, from old Suntour LePree to Campy something to Superplate-deer-head to Huret Duopar (do not recommend) to Shimano M952 XTR (works best imo) and similar era XT. It's all capable enough. Some say the ratchet teeth in the power ratchet are not close enough together for the small 9-speed jumps, but I have not found this to be a problem. I usually click over three teeth to change a gear, and rarely have to trim the lever back after a shift.
I have also used Campy NR downtube levers with Suntour Cyclone M2 that has had the limit screw stops filed down to shift a 9-speed road cassette on my Vitus. The shifter moves through nearly 180 degrees, but it works and it's easy enough to do that I can shift with mittens on.
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Owner & co-founder, Cycles René Hubris. Unfortunately attaching questionable braze-ons to perfectly good frames since about 2015. With style.