With a 34T/11T as the ratio that lets you go fastest, yes I do spin out, but mostly just on the road. Running SPDs could have something to with it maybe? Being able to spin faster more easily perhaps, just making guesses
1×9 is on my 2nd bike which I ride on local terrain where the steep climbs are much shorter but generally the hills aren’t as steep. I don’t have a lot of flat out descents either.
Not having any choice other than to use a 34T front ring (the 32T rear isn’t engaging properly at the moment either so its a bit harder) forces me to put a little effort in on shorter local rides where I may otherwise get lazy and drop down to the granny ring
On my main bike I do have a standard 3×9 setup which gets used for longer rides elsewhere, where long steep climbs are commonplace and not destroying myself on the first hill helps to get me round the rest of a ride with ease, though I don’t always drop into the granny ring. I find it being a full suss bike means I drop into the granny ring more often/easily, it doesn’t seem to put the power down quite like the hardtail does
The big ring is good for any road sections between trails. I often tend to use it on faster downhills too