Translation:Vanya Chernov can play both guitar and piano.
You'd probably have to do an etymological search to figure out the difference. The guitar has been around longer than the piano, and the word probably came into the language long before the piano made it's appearance. http://www.guyguitars.com/eng/handbook/BriefHistory.html
So, yeah, it's a native Russian word just as much as "guitar" is a native English word. It appears in various respelling in many languages, all of which are clearly an expression of "guitar".
The third person singular conjugated verb in this sentence is умеет, which could be thought of as “is able” or “knows how.” When partnered with the infinitive form играть (“to play”), it combines to become “knows how /// to play.” So since умеет is already conjugated, we wouldn’t need to conjugate the infinitive that follows it. I hope this helps. Let me know if I was not clear.