Title basically says it all. Will it be as jangle-y, shimmery as a real p90 or basically sound like a humbucker's interpretation of one?
It should sound fairly close, due to the fact that it's the same basic construction (slug polepieces, single coil, bar magnet below coils) but it will sound somewhat different due to the metal baseplate and housing and the slightly different geometry.
Current Gear:
LTD MH-400 with Gotoh GE1996T (EMG 85/60)
PRS SE Custom 24 (Suhr SSH+/SSV)
Ibanez RG3120 Prestige (Dimarzio Titans)
Squier Vintage Modified 70s Jazz V
Audient iD22 interface
Peavey Revalver 4, UAD Friedman BE100/DS40
Adam S3A monitors
Quote by Anonden
You CAN play anything with anything....but some guitars sound right for some things, and not for others. Single coils sound retarded for metal, though those who are apeshit about harpsichord probably beg to differ.
close enough for 99.9% of the audience.

not close enough for cork sniffing tone nazis...

its really up to your ears.
I wondered why the frisbee was getting bigger, then it hit me.
Close, but not identical. Some will come closer than others.
Keep in mind though, not all P90s sound the same anyways.
No gods, no countries, no masters.
More guitar, less Ultimate-Guitar.
Be Serious.
Shorties represent!
Ibanez SZ520/Ibanez ORM-1/Ibanez RG7321/Pocket POD/Crate GX/Boss HM-2
More or less the same, yes. Again it comes down to.. not all P90's sound the same, the P90 in my guitar sounds woody and neutral, neither of those are words you used to describe your idea of a P90.

Nonetheless, from certain brands, humbucker sized P90s sound spectacular, I'm tempted to push you towards Kent Armstrong and I've heard a few guitarists with KA humbucker sized P90s and they sound amazing.