I think he could indeed stand a chance against some members of the royal guard; to be fair, however, we don't know the full extent of their physical abilities.

One of Pouf's main strength are his hypnotic scales. The Hunters managed to see them before the invasion, so they weren't a threat, but they are indeed very dangerous. I don't think Killua would be immune to those (and before anyone complains: Killua has made it very clear that his body is immune to some poisons and toxins, not all of them). I do agree with Kanmuru he'd overhwelm Pouf, too, but the problem is Pouf is almost undefeatable if he splits up. He can just run away whenever.

I don't think in 14 years he'll already be as strong as Gon-san, though he'll definitely be a beast. It's hard to say if he could defeat Pitou and Youpi, since we know so little about their max power.

Something to bear in mind (I'm saying this after reading the other replies) is that Killu aand Gon got so strong in two years also because they went from not knowing Nen to knowing it; however, the speed at which they grow should slow down sooner or later, we can infer it just by looking at other characters. This does not mean it will stop: both have started learning so early (especially Killua, he has been trained since his birth by the very best and is known to be very talented) and are blessed by huge talent and determination, that I think it wouldn't be a stretch to assume they will eventually get stronger than old Netero (don't know about Prime Netero, we've never seen him). Still, since Nen takes a very long time to master, they may not become as proficient as him in just 14 years.