Look for the contrabass clarinet part.

It would be best to speak to your band director. They would have a better idea and would select parts that they would have you to play.

Baritone in treble clef is a Bb instrument, and thus you could play. Also a possibility is the bass clarinet part.

Others, the Euphonium part could be played, but would require someone to transcribe parts from bass cleff to Bb treble clef. That particular band director may or may not have someone on board to do that, which means you might have to do your own transcribing.

Reason why I say this, is in cases where for example, we were out of alto sax music sheets, then would use alto horn or alto clarinet parts. For Bb tenor sax, baritone treble clef, etc.

But, first off, speak with the band director of the band you want to join, and that you want to play bass sax. If accepted into the band, he'll work out the music he wants you to play.