Pluto was discovered/confirmed in 1930 by a 23-year old Kansas farm boy, Clyde Tombaugh, using a telescope at the Lowell Observatory in Flagstaff, Arizona.
After a 2 month search for names, an eleven-year-old schoolgirl, Venetia Burney, from Oxford, England, suggested the name Pluto to her father who passed it on to an astronomy professor who passed it on to colleagues in the United States.
New Horizons’ almost 10-year, three-billion-mile journey to closest approach at Pluto took about one minute less than predicted when the craft was launched in January 2006. The spacecraft threaded the needle through a 36-by-57 mile (60 by 90 kilometers) window in space — the equivalent of a commercial airliner arriving no more off target than the width of a tennis ball. Source: NASA 2015-07-14
When the New Horizon spacecraft was launched in January 2006, Pluto was still the 9th planet. Nine months later, in September, Pluto was reclassified as a dwarf planet. It belonged more to the Kuiper belt (or Trans-Neptunian objects) than with the rest of our eight planets.