Yes, with caveats. The poise and colossal weapon buffs make strength builds genuinely fun for the first time since launch. However, if you rely on the original Moonveil or Rivers of Blood cheese, 1.09 nerfs those significantly. Also, note that some popular cheat tables (trainers) do not work on 1.09; you must wait for an updated CT file.
If you are still sitting on an older version (like 1.05 or 1.07), installing the 1080 update first is mandatory. Here is what 1.08 introduced: elden ring update 1080 1090 elamigos updated