in most cases it should work, because it will contain only bug fixes, but we do have cases in the past that due to some missing symbols there was a breakage so it was not working.
You can judge if it's worth it by the changes: https://code.qt.io/cgit/pyside/pyside-setup.git/tree/doc/changelogs/changes-6.8.3 (those are the highlights, a few minor ones were also around).
If you find something, let us know so we can keep track of that for the next bug-fix releases of 6.9.x
Also keep in mind 6.8.3 is the last release of the 6.8 series, but the source code of 6.8.4 will be around in a year after that release (which is still not planned)