This is a common, and easy, procedure, but there are a couple of things involved.
First, whether or not you have a number showing in the document, all pages have numbers, and second, InDesign complains if the same number is used on more than one page, which sounds like a problem, but "same" means both the same counting sequence AND same numbering style, so you don't want two pages numbered "1" but you can have a page numbered 1 and a page numbered i (small Roman numeral), for example, which is the traditional way of numbering front matter pages, so let's start there.
In the Pages Panel you will notice that the first page of your document has a small triangle above the page icon. This is the Section start marker and indicates where the page number sequence begins. Right-click on the first page icon and from the context menu choose Numbering and Section Options. In the center of the dialog you will see a drop-down list for number style and you should pick any thing you like, other than the style you will use for the main part of your book.
Now right-click on the page where you want to start numbering at page 1 (in your case, that's page 9), again choose Numbering and Section options and be sure the box at the top is checked to Start Section, the radio button for Automatic page numbering is selected, and change the starting number from it's current value to 1. Go to the Numbering Style drop-down and choose the style you want to use for the main section of the book, click OK and you're done.
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