how many iPhoto libraries can I sync with iCloud?

Yes, see this -- iCloud: iCloud storage and backup overview

One shouldn't consider using the iCloud Photo Library as backup. It is primarily a syncing service providing you with the convenience of having your photos available across all your Apple ID-controlled devices.

You could back up the library databases to iCloud Drive, but once again, this is not a core strength of iCloud Drive. I say that because at present, the local files will still be on your local drive as well as in the cloud.

Not moved to iCloud. Synced with iCloud.

LACAllen I sure do wish I could pick your brain as I've got some interesting questions for you! I do like your writing and cut of you gib!

Thanks. I often get tagged with being the opposite.

LACAllen any ideas on how I can connect with you?

Nope.

LACAllen Eureka! I created a temporary alias for you to reach out to me if you so wish.

It's my handle here, on the forums, @icloud.com

I'll leave the alias open for a couple days to hear from you.

Ok. Done.

What OS and IOS version are you using? If you don't want to use iCloud Drive, you will need to compile all the photos into one Library to use iCloud Photo Library.