As everybody said, whimsicott doesn't learn whirlwind. But Murkrow does, and is the only that can use this combo (Whirlwind+Prankster ability).well he got it from whe whimsicott thread... so it SHOULD learn whirlwind which im pretty sure it does since it learns hurricane, and it also explains y i made my statement on the dragonite thing...
Also nitpick: Shuffle moves= priority -6, Prankster: give non damaging moves +1; that makes shuffle moves used by prankster -5 priority.
@TM13IceBeam: And you are right, the Whimsicott partner is just for Priority stun spore, so dragonite does not waste a turn using T-Wave. I'm assuming doubles battles, though.