Suggestion

Unfortunately, this is not possible now.

But there is a workaround.
The idea is to create additional sidebar for homepage only.
In this case you’ll have an ability to configue widgets on homepage in a different way.

Here is another way how to perform this task: http://ww.wp.xz.cn/support/topic/allowing-for-multiple-page-layouts

But for you I recommend frontpage sidebar solution.