Context: a group of girls hear a rumor that one of the female students is actually a dude. They go investigate, questioning the girl, and it turns out she uses boku as pronoun.
are... Aozora-san φ ichininshou φ "boku" nano? あれ・・・青空さん一人称「ボク」なの？ Huh... Aozora-san's first person pronoun is boku?
kono jiten de {sude ni} auto-ppoi desu ga... この時点ですでにアウトっぽいですが･･･ By this point, [it] already seems [she] is out, though... (literally.) Given this, it already feels like the rumor is true...
kono jiten de - "by this point in time," used in the sense of "given that this happened, we can already say something else is true," and the sort.
auto - "out" in the baseball sense. When someone is "out" it means they failed a test by going outside what is allowed. In this case, it would be "safe," seefu セーフ, if Aozora is confirmed to be a girl, but it seems she's "out" already (i.e. it's confirmed she is NOT a girl) by using boku.
bokukkono kanousei gaarukaramada nantomo... ボクっ娘の可能性があるからまだなんとも･･･ There's a chance [she] is a bokukko, so [we can't say] anything yet... (incomplete sentence.)
mada nantomo ienai まだなんとも言えない [We] can't to say anything yet. (i.e. we can't say for sure that she's a boy based only on this information.)
