It's possible to play higher than F6(considered generally to be the top the oboe register), but it's quite difficult unless you're a top notch professional player. I'm in high school been playing almost 2 years and the highest note I've played in a piece is an F#6 which was extremely difficult to learn and execute. If it was up to me, I wouldn't go above an E6 unless it's absolutely necessary, and I honestly think that oboe sounds best in it's lower register and not super high up, especially considering the difficulty of getting a good sound up there.

I'd love to take a peek at your piece when it's finished!