and then trip them with my AoO when they move in to attack me?
Not unless you also take Weapon Focus (whip), Whip Mastery, and Improved Whip Mastery. Otherwise, you don't threaten at reach with the whip.
So that adds up to a LOT of feats. Once you have all seven necessary feats, it still relies on a successful Acrobatics check (otherwise you provoke AND lose the Canny Tumble benefit) as well as a successful trip attack (when you don't even have Improved Trip to improve your chances.) And you can't use it with a full-attack. So, not OP.
Not quite...
A Whip can attack targets at 15ft, 10ft AND adjacent targets, however, they do not threaten the squares into which they can attack.
A Scorpion Whip only has the Performance special quality, not Reach, Disarm or Trip. Therefore only attacking adjacent foes. It gains those properties as long as you also have Exotic Weapon Proficiency: Whip, as that allows you to treat a Scorpion Whip as a Whip (functioning as a One-Handed weapon instead of a Light weapon) that deals lethal damage and ignores the +1 armor or +3 nat armor rule.
That being said, Canny Tumble would still work for getting in that Sneak Attack damage if your Acrobatics is successful.
A whip deals no damage to any creature with an armor bonus of +1 or higher or a natural armor bonus of +3 or higher. The whip is treated as a melee weapon with 15-foot reach, though you don't threaten the area into which you can make an attack. In addition, unlike most other weapons with reach, you can use it against foes anywhere within your reach (including adjacent foes).
Using a whip provokes an attack of opportunity, just as if you had used a ranged weapon.
You can use the Weapon Finesse feat to apply your Dexterity modifier instead of your Strength modifier to attack rolls with a whip sized for you, even though it isn't a light weapon.
Weapon Feature(s): finesse, reach.
As RumpinRufus pointed out, you would need to build up to Improved Whip Mastery as well to threaten at 10ft and 5ft (assuming your natural reach is 5ft).