Arbusers

Hello,,I notice an arb

Colorado Rockies - Los Angeles Angels
Listed pitchers J. Francis - D. Haren
Over 9.5run  Expekt 1.83
Under 9.5run Pinnacle 2.31

It's 2.4% arb, good.
But I don't know what this bet mean.
It seems bet on players rather than team.
So..what is that mean someone over 9.5? and what is "run"?
May someone help explain me this game?
Thanks a lot.

The o/9.5 and u/9.5 is for the game. The pitchers must both start for there teams for the bets to stand. bookies have different rules in baseball so beware that both bookies have the same rules.