With the faster release cycle, we don't plan to list previous versions on the download page except where OS compatibility was dropped (which is why 7 is still there).
You should contact the plugin developers and ask them to test their plugins for compatibility with Zotero 9 and mark them as compatible. Plugin developers have had weeks to update their plugins, likely with very few or no changes.
Current plugins have unrestricted access to Zotero and your system, and there have been plugins with major data-loss bugs before, so it’s critical that plugins are tested and maintained and the developers are responsive. If the plugins aren’t being maintained, you shouldn’t use them.
I've been using Zotero for years. Reverting to an older version until the plugins catch up has never been an issue. If that's going to be the case moving forward, then there should be a warning.
The plugins I am using are regularly updated but, from my understanding, most are run by volunteers. They may need more than a few weeks to update. I am sure they will be updated eventually. But, currently, my workflow is interrupted and I need to revert to a version where the plugins work.
As of now the easiest way to check each of your collection of plugins for compatibility with a particular Zotero version is this plugin repository: https://zotero-chinese.com/en/plugins/
When Zotero does an update it will disable your installed plugins that are not compatible with the updated version. But sometimes there is actually a newer version of a plugin available that was not auto-installed for your previous Zotero version because it was not backwards compatible with that Zotero version. And AFAIK there is no automatic means to recognize that for disabled plugins when you update Zotero, such that Zotero would then find and install the newer, compatible plugin version (I have encountered that problem). But the above repository should show you that a new version does exist, which you can then install.
Two things: 1. updating a plugin's manifest.json to be compatible with a new version of Zotero is a tiny change. One single line. Of course you'd do that only if you've first tested it, but even if you're just providing a plugin in your free time, it shouldn't be a lot of work.
2. Which plugins specifically are you talking about? Maybe we can help more concretely then.
Upgrade Storage
With the faster release cycle, we don't plan to list previous versions on the download page except where OS compatibility was dropped (which is why 7 is still there).
Current plugins have unrestricted access to Zotero and your system, and there have been plugins with major data-loss bugs before, so it’s critical that plugins are tested and maintained and the developers are responsive. If the plugins aren’t being maintained, you shouldn’t use them.
The plugins I am using are regularly updated but, from my understanding, most are run by volunteers. They may need more than a few weeks to update. I am sure they will be updated eventually. But, currently, my workflow is interrupted and I need to revert to a version where the plugins work.
https://zotero-chinese.com/en/plugins/
When Zotero does an update it will disable your installed plugins that are not compatible with the updated version. But sometimes there is actually a newer version of a plugin available that was not auto-installed for your previous Zotero version because it was not backwards compatible with that Zotero version. And AFAIK there is no automatic means to recognize that for disabled plugins when you update Zotero, such that Zotero would then find and install the newer, compatible plugin version (I have encountered that problem). But the above repository should show you that a new version does exist, which you can then install.
1. updating a plugin's manifest.json to be compatible with a new version of Zotero is a tiny change. One single line. Of course you'd do that only if you've first tested it, but even if you're just providing a plugin in your free time, it shouldn't be a lot of work.
2. Which plugins specifically are you talking about? Maybe we can help more concretely then.