...You do realize that planting explosives is a lot more difficult than planting a spy, and much more likely to be discovered, right? And that one does not imply the other? The more reasonable assumption is that Sound and Sand are secretly allies, and that Kabuto is a spy for one of them, who is about to kill someone who discovered him. There's no reason to assume a larger plot.
Why would planting explosives (remember, in Narutoverse explosives are drawings on strips of paper) be harder than planting a spy?
[X] Run off in the direction the spy went. For all you know, they were going somewhere vital. Even if they got caught, they might still be alive. You're just one genin, you need someone else to corroborate your story.
-[X] Stunt 1: Even as you run, you fish out a pen from one of your pockets, and, with an ease and fastness born of long, fruitful fuinjutsu practice, scribble a brief note on one of your tags, summarizing what you learned. In another single and quick motion you attach it to a kunai, and launch it, soundlessly, out of your sight where you know, without a doubt, it'll end up lodged in a backdoor of a local restaurant, run by a retired, but loyal, konohan chuunin. Even if you fail, even if you die, the information will still get to the hokage.
-[X] Stunt 2: This is a foreign Jounin, beyond your skills in almost all respects, but this is also Konoha territory. You recall Gai-sensei's prohibition on the use of explosive tags outside of life and death situations. As it turns out, this is a matter of not just survival, but, seemingly, entire village security. You slap on and activate n explosive tag as you flit past a chimney. Another on a roof corner decoration. A third on a box of forgotten fireworks...wait, what the hell was that doing there?! You take a sudden change in direction. That should be enough noise to draw in Konoha's patrols, enough direction to point them towards the fight.
Ok, so:
1) We are on the roofs. What trees? What supporting pillars?
2) Corrected grammar
3) Left a message for someone to pick up. Mission first, after all.