Moon is not spherical as per Jain Scriptures. Sun and moon both are the Vimaan(vehicle) of Jyotisi dev.
They are hemispherical in shape as per this diagram:
Sun and moon both have the idols of Jinendra Bhagwan. This is the reason why chakravartis in ancient times used to bow hands looking at moon and sun. They could actually see the idols in them.
Also, there are many moons and suns, not only one. The counting is like this:
To read more, refer to this book written by Br. Kalpna Didi.