Share icons on blog post excerpt page?

While Jetpack doesn’t include such an option, you can follow the second part of this tutorial to add the buttons in any place you want:
https://jetpack.com/2013/06/10/moving-sharing-icons/

In your case, you could hook them to the get_the_excerpt filter, as explained here:
https://codex.wordpress.org/Plugin_API/Filter_Reference/get_the_excerpt

You could try to add the following to a functionality plugin to add sharing buttons to all excerpts. I haven’t tested that code, but it should work:

function jeherve_add_sharing_excerpts( $excerpt ) {

	// Let's build a string containing sharing buttons and likes, if they're activated.
	$sharing = '';

	if ( function_exists( 'sharing_display' ) ) {
		$sharing .= sharing_display( '', false );
	}

	if ( class_exists( 'Jetpack_Likes' ) ) {
		$custom_likes = new Jetpack_Likes;
		$sharing .= $custom_likes->post_likes( '' );
	}

	// Now let's add that to the excerpts.
	return $excerpt . $sharing;
}
add_filter( 'get_the_excerpt', 'jeherve_add_sharing_excerpts' );