I think you're reading a little bit too much into this 9-speed thing. That bike does not only have 9 speeds... The '9-speed' refers to the 9 cogs on the rear cassette, combined with two chainrings on the crank. That provides a total of 18 possible gear combinations, or 'speeds'.... though only 12 or 13 of those combos are really useable with out severely crossing the chain or causing rub on the front derailleur. Assuming that it fits you properly, that bike should be more than adequate for your ride.