Can i hide or disable the option for owners to make payments in their online owner portal? Can i also hide all the billing information on their account so they can't see their billing history?

Yes, if you manage the HOA and you would like to disconnect the online payment processing feature from the owners portal you can login to your manager dashboard and on the menu on the left hand side of the page click on Tools>Settings and at the bottom of the page there is a section called "Owner Login: Restrictions" 

Here is a screenshot of what it looks like:

If you click on the radio button and the option to "remove all billing verbiage and buttons from owner login portal" and it turns "blue" it indicates that you be removing the following sections of the owner portal(remember to click on save down in the bottom right hand corner of the page):

-The Billing History section at the bottom of the main owner portal account page

-The Print Invoice button

-The Make a Payment button and the Make a Payment menu item on the main side menu of the page

-The Billing Section on the right hand side of the main owner portal account page

-The Recurring Dues section on the right hand side of the main owner portal account page

-The Balance section on the top right hand side of the main owner portal account page

-The Payment Settings menu item on the main side menu of the page

Here is a screenshot of the parts that are disabled(circled in red)