You should be able to cut it down but you will need to carry a side stand plate to set down before using the side stand. Or you could drill the end of the stand and bolt a plate of some sort to it.
However keep in mind that as you cut higher and higher on the side stand you are also reducing the horizontal distance from end of the stand to the bike. This distance is important to keep as wide as possible to reduce the chance of the bike from toppling over the top of the stand. This can be compensated for partially by bolting a wider plate on to the bottom of the stand.
However keep in mind that as you cut higher and higher on the side stand you are also reducing the horizontal distance from end of the stand to the bike. This distance is important to keep as wide as possible to reduce the chance of the bike from toppling over the top of the stand. This can be compensated for partially by bolting a wider plate on to the bottom of the stand.