If you mean can you have stories for both prompts in the same document, I'm pretty sure the answer is 'yes, just make sure it's clear where each one starts'. On the other hand, looking at your wording and the doc makes me think you meant 'can I write one story using both prompts', which...is a pretty neat idea, though I have no idea if that's an okay/done thing or not. Someone else want to clarify? Do we even have an answer for this yet?
A Bit of Light Betaing (because I noticed some things but don't actually have much free time right now):
In terms of the actual story, which I glanced through a very little bit (okay, I mainly read through the ending for some reason): I see you have a Klingon in there. That's cool! Is the Klingon meant to be a particular Klingon (I believe there are only two currently identified as agents--Morgan's former partner, and Kozar)? Or is he a new one? Either way, he needs a capital letter on 'Klingon' (see Memory Alpha for how it's used--which is quite simple: just capitalize it!--and for more information on Klingons).
Speaking of more information on Klingons: what September says to him? That should get her a *very* angry Klingon, not a Klingon who gets distracted by the ball of whatever it is (do I...want to know? My current guess is 'horse dung', except...from the centaur? Which sounds like a slur against centaurs, but...)
And, of course, speaking of the ball and the interaction with the Klingon and everything: it seems...kind of nonsensical. Even leaving aside the Klingon not really reacting to the insult apart from stomping over, I don't understand what the ball is, why it's there, what the Klingon knows about it (or why he should care), and, perhaps most importantly, why the Klingon feels so urgently responsible for it that it's the only thing he focuses on.
Also: er, would a Babysitters Club character really swear like that? I was under the impression they didn't really do that in those books, though my knowledge admittedly comes from the first few Snark Squad reviews of the books and not from reading them myself. Also: Babysitters, no apostrophe. There's some ridiculous reason in one of the first few books.
One more small thing: Kelly says she comes from a "Ben 10 Men In Black crossover." Crossovers are generally denoted by either an x (as in Ben 10 x Men in Black) or a slash (as in Ben 10/Men in Black). As well, titles of movies, TV shows, books, magazines, and so on (probably games as well) are usually italicized, giving us "Ben 10/Men in Black crossover." And, lastly, Men in Black doesn't have 'in' capitalized, according to iMDB and grammar rules. (Similarly, Star Trek has no hyphen and gets italicized.)
...and one last thing: I don't see any mention of which prompts you've used, and I can't really guess (partly because I don't exactly have them all memorized). So: which prompts have you used? And might I suggest putting them somewhere visible in the doc, either before or after the story text?
Hope that helps a little.
~DF