I suspect circles are impossible. Boomerangs fly in a curved path and the lift opposes gravity. The nett result is a roughly circular path, but it tends to rise at first then fall.

In space, there is nobody to hear you squeal with delight, but I would expect a spiral path with the lift force causing steady ascent of the focus of the circle.

As air friction robs the boomerang of both spin and forward momentum, the path will evolve, but the details are beyond me. (less spin means less lift, so the spiral will tend to a finer pitch with time, but the lift is a force and until terminal velocity is reached, the pitch will initially INCREASE. Less spin means less gyroscopic effect, therefore less curvature, so possibly a more open circle?)

(And I'm still not convinced that without gravity the boomerang will behave the same in space. Isn't there some subtle effect due to precession of the axis of spin?)

basically, we need a bigger space station and then all these things can be tested out the proper way...