Did you restart your Roku Soundbar before re-installing the Hulu channel? That step is crucial when performing the troubleshooting. If you haven't tried the suggested order (remove > restart > re-install), we suggest giving it a shot once again.
We also recommend restarting the soundbar from the Settings menu by navigating to Settings > System > System restart > Restart.
Check for a Roku system update. If your problem is only with the Hulu channel, this step may have no effect, but it's best to make sure your device is up to date. Go to Settings> System, check if there is a system update, and if so, please install.
I also have the Roku Sound Bar and the Hulu app keeps crashing on it for me. It just crashed back to the main Roku screen. Doesn't seem to crash on Apple TV receiver though. Anyone else experiencing this?
In addition to what @Tivoburkee suggested, we would recommend checking for a channel update to see if that helps. You can update the channel by selecting the channel on the Home screen and pressing the * button > Check for update.