Yes, there is a Widget for that.
In your WordPress admin, go to menu Appearance->Widgets.
Drag&drop the widget “WPSOLR Sort list” to the widget area your theme is providing. It could be on your theme search page for instance.
I cannot see the “WPSOLR Sort list” widget in my admin or in my front-end widget area.
Currently, the widget appears only on search pages (pages which url contains ?s= ).
And for WooCommerce ?
For WooCommerce, no need of a sort Widget. The standard sort drop-down list content can be replaced by the WPSOLR sort items. Check out in the WooCommerce sort documentation.
