A couple 'o things:
1) Citabrias must be bad, maybe even dangerous, for aerobatics, as they are only utility category airplanes being rated at +5/-2g's
2) FAR 23.3 states: "(b) The utility category is limited to airplanes that have a seating configuration, excluding pilot seats, of nine or less, a maximum certificated takeoff weight of 12,500 pounds or less, and
intended for limited acrobatic operation. Airplanes certificated in the utility category may be used in any of the operations covered under paragraph (a) of this section and in limited acrobatic operations."
3) FAR 23.151 states: "?23.151 Acrobatic maneuvers.
Each acrobatic and utility category airplane must be able to perform safely the acrobatic maneuvers for which certification is requested. Safe entry speeds for these maneuvers must be determined"
4) FAR 23.221 states: "(b) Utility category airplanes. A utility category airplane must meet the requirements of paragraph (a) of this section. In addition, the requirements of paragraph (c) of this section and ?23.807(b)(7) must be met if approval for spinning is requested." and "(c) Acrobatic category airplanes. An acrobatic category airplane must meet the spin requirements of paragraph (a) of this section and ?23.807(b)(6). In addition, the following requirements must be met in each configuration for which approval for spinning is requested:
(1) The airplane must recover from any point in a spin up to and including six turns, or any greater number of turns for which certification is requested, in not more than one and one-half additional turns after initiation of the first control action for recovery. However, beyond three turns, the spin may be discontinued if spiral characteristics appear."
So it would seem that aerobatics should be fine as long as they are part of your test program. That said, I would like to know more about any first hand experience there is out there with spins in 9's and whether the 1 1/2 turn spin recovery requirement is what prompts Vans to prohibit spins, or if there is other behavior that drove this decision, particularly (obviously) bad behavior.
Tim