The SV9 allows for a 90° rotation of the horn diffuser to mount the speakers horizontally instead of vertically.
If the cabinet were rotated 90 degrees to its side, you could then rotate the horn to maintain the 90 horizontal by 60 vertical pattern. If you want to have 90 degree vertical by 60 degree horizontal coverage with the box standing up, you can also rotate the horn for that. The speaker's shape includes only a slight angle, so it's not enough to make it useful as a "wedge" monitor. You could use it as a front fill in either orientation.
To go a step further, the horizontal off-axis performance is much better with the box oriented vertically. When you rotate the box to "lying down", the horizontal dispersion isn't as even, and rotating the horn does very little to improve the pattern. In short, because out ears are offset horizontally, it's best to stack the highs an mids vertically, so whenever possible, use them standing up...