Well, it kind of depends on what you call a “planet”. Pluto used to be officially a planet, but then astronomers made it officially a “dwarf planet” (see http://en.wikipedia.org/wiki/Dwarf_planet ). And there are at least three more “dwarf planets” out there beyond Pluto. One of them, called Eris, is actually bigger than Pluto, and it was found in 2005.
Since 2006 there have only been 8 planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Astronomers decided Pluto isn’t really a planet and it’s now classed as a “dwarf planet” – some of them are still arguing about this though! There are other dwarf planets too – Ceres, Eris, Makemake and Haumea and maybe others we don’t know about yet. So if you include these, then yes, there’s more than 9.