First off, did you purchase your 2018 from Corel? Maybe they could have the 32-bit version that you can download? Yes, some plugins were never updated by their creator to be used in modern 64-bit programs which is why it is always recommended to install both versions of PSP.
If you reinstalled PSP9, you need to install the patches (they are available in the Resources > PSP Patches section of the navigation here). I am not sure what bug each patch addresses but it is a good idea to install any patch the comes for a specific version of PSP.