I wouldn't make the assumption that the Cayman is more fun. The 997 has a lot more power than an '09 2.9L. The gearing is also numerically higher in the 911, making it feel even more responsive than the power difference would lead you to believe.
Handling is a mixed bag. The rear suspension in a 997 is more sophisticated, and you can feel that, but the combination of >60% of the weight on the rear wheels combined with a very short wheelbase can make the 997 dip and bob like a porpoise on some roads. On smooth roads it is difficult to tell the difference. The 997 also has more snout than the Cayman, and it doesn't like some driveways (like mine).
FWIW, I think the Cayman is better looking.
One of the let-downs about the 997 is that the interior is nearly identical to Cayman, save the shape of the instrument area of the dash, and the inclusion of two gauges. For a car that is so much more expensive you would think you'd get better materials, more style, etc. Also, the rear seats in a 911 are just dumb, in my mind. The Cayman, with secure front and rear storage, also strikes me as more practical, especially for trips.
A lot would depend on the 997's condition, mileage, and options. Can you give us more information?