F1 Visa stamped on page 9 leaving earlier pages blank

The first time you use a US visa to enter the US, the CBP officer will stamp your admission, and will then place a second stamp across both passport pages, the one containing the visa and its facing page, so that the stamp crosses the edge of the visa and the passport binding. So the consulate will try to place the visa on a page where the facing page is blank. Otherwise there is no significance to which page is used.

Note that in many countries' passports, the first several pages are used by the issuing country for your personal data page and general information, so it's possible that page 9 (and its facing page) are the first available pages for visas and other stamps. In my US passport, for instance, the first pages usable for visas/stamps are facing pages 8 and 9.