Sorry for my misunderstood in my previous post.
I did some tests and the result of using ScaleBarPrinterLayer in the Web Edition is "The Layer must be opened before you can perform this method", and it had been fixed in the latest Daily Builds version 188.8.131.524(Production) & 9.0.343.0 (Development) or higher version. Please get the fix from Product Center and have a try again. If it is not the same as your issue, please provide more information. if possible could you please upload a simple project to show us your issue.
If you have any issue, do not need to vote, only need to let us know.
For the moving/sizing of PrinterLayer items, you need to add it to Enhancement Tracker. Our developers will conduct an investigation to determine whether to add it in the next version. Enhancement Tracker will serve as a reference.
If something misunderstood here, please provide more information.