woocommerce and is_user_logged_in() if not redirect to homepage

You are going to want to insert your code at the top of the page templates for the Woo pages you would like the redirect to affect rather than the functions file. So for example if you want to redirect users when they try to access an individual product page you could put it at the top of the plugins->woocommerce->templates->single-product.php page.

When editing templates though I would recommend making a copy and placing it in your theme directory, so that when Woo updates it will not override any changes you made. So for the example I gave above (applied to my theme). I would copy single-product.php and place it in the themes->agency file and then make the changes to that file, there. Your theme will then always use that file before the one in the Woo template file.