What is the typical value of maximum lift coefficient for aerobatic aircraft?
First, don't take the two-dimensional value from an airfoil chart and use it for the full aircraft. Subtract 15-20% for wingtip margin and fuselage influence. Wingtip margin means that the wing is less loaded towards the tips to keep a lift margin for aileron control and to avoid a tip stall.

Next, aerobatic aircraft have lower maximum lift coefficients than GA aircraft. Their wing loading is lower, so they can afford this. A symmetric airfoil mounted at zero incidence has proven to be the best choice, and while some older aerobatic aircraft use cambered airfoils, the camber creates a distinct disadvantage in transitions from normal to inverted flight and vice versa. 

And last, the maximum lift coefficient depends on quite a list of parameters. If you need a value for the calculation of structural loads, make sure you add enough strength to cover the increased lift possible with high pitch rates.

If you need a figure for a single-seater piston-powered aerobatic aircraft without flaps for the estimation of minimum speed, use a lift coefficient of 1.3.