Hi,
Well, I don’t really think you can make those links “crawable” as they are not actually links, but rather pure HTML anchor tags styled in a way that users can click on them to navigate.
The jQuery UI Datepicker ships by default with the WordPress official core framework, and all our plugins do is to actually load that JavaScript dependency through the WordPress native functions.
We do not generate those “links”, they are actually generated by the jQuery UI Datepicker library, and so we have no power to control their contents or “href” attributes. They just cannot be links to be followed, but they are indeed anchor tags.
Since there is no “href” attribute, the tool you are using should simply ignore those “links”, as there is nothing you can do to change that structure, I’m sorry.