For this you would use an acf/pre_save_post filter to create the new post.
http://www.advancedcustomfields.com/resources/acf-pre_save_post/
Then get the current term id for the page being loading and either set the taxonomy term for the post by using either standard WP function of using the ACF update field function to set a taxonomy field.
https://codex.wordpress.org/Function_Reference/wp_set_post_terms
http://www.advancedcustomfields.com/resources/update_field/
