Sticky bucketing is supported in version 0.2.3 of the Go SDK. That said, no actual sticky bucketing will happen until you enable it in your code bases.
What I might suggest though is enabling it in GrowthBook first, then going to each of your active experiments and disabling sticky bucketing per experiment. That way once you're ready to implement at the code level you can do so with new experiments only without risking biasing in-flight ones.
That said, if you are attempting to keep your bucketing sticky across users irrespective of device/environment (mobile, browser, backend), then it's incumbent upon you to make sure the same id is available in each environment (go, kotlin, ios). Otherwise, you are effectively experimenting on "user devices" rather than "users". Not necessarily a bad thing, just something to watch out for.