fmp12 is not really made to sync files. You can use iTunes to copy your file from your desktop to your ipad. This will overwrite your current file on your ipad.
You can check out 360works webs site for a plugin that syncs files. http://www.360works.com/.
Or you host your file from a server and use iPad with FM GO to connect to it as a client. That eliminates the synch issue, but requires a reliable wireless connection to the hosted database.
BTW, there's a section of this forum FM Go Forum, especially set up for FM GO questions. See the tabs at the top of your screen.
iCloud is a static storage system, I believe.
Some have suggested using Dropbox, because that will store local copy.
Most suggest that is a bad idea.
Your computer, if it is on a fast internet connection can host the database WHILE FMP is running for 9 users.
You would have to setup your router to port forward requests to your computer.
iOS iPad FMP GO ver12 info links
FileMaker Go for iPad Help
Connecting to Databases | FileMaker Go for iPad Help
FileMaker Go works as a client with FileMaker Pro files that are open, hosted, and shared on a Wi-Fi or cellular (3G) network. Data is updated interactively on the device and on the host for the duration of a session.
Filemaker Inc - Filemaker Pro and Filemaker GO
FileMaker Go Database App for iPhone and iPad | Overview
iOS Filemaker PDF
Using FileMaker 12 Runtime files with FileMaker Go 12 April 15, 2012