If you haven't done so already, restart your iPad and computer. It looks like you've had a chance to review If your iCloud Contacts, Calendars, or Reminders won’t sync, which is a great first step.
We understand that iCloud isn't syncing as expected. Thanks for taking the time to post in the Apple Support Communities.Even though Apple broke up iTunes into several different apps - Music, TV and Podcasts- you won't find a "sync" app on your Mac. How to sync your iPhone or iPad if you use a Mac.