Well, if it was any Cannabis species, it's at its darnedest and flowering already, in the prime of being top priority illegal, because the leaves are growing alternately. Besides, the leaflets aren't serrated enough, I don't see long petioles, and the stem isn't ridged. If it was C. indica the colour is completely wrong - they're usually a dark green; C. sativa is usually lime green; and C. ruderalis is also a rich green colour. Even crosses between the above species won't make something that looks like that. Unless this is a cross between Australian "B" Cannabis.
Don't ask me why I know all this (at least publicly)....
Um, let's get back to that caterpillar at hand, shall we? That caterpillar looks like it may very well be a moth larva of some sort. I'm not experienced in this field yet so I'll leave it at that. Keep it alive!
Amori