No need for an install routine or a DB option

I think this plugin can be reduced down to a single line:

add_filter('woocommerce_allow_marketplace_suggestions', '__return_false');

There’s no need to check if Woo is active as the woocommerce_allow_marketplace_suggestions does not exist if Woo is not active.

What’s the purpose of your DB option? I’m guessing that could be removed as well.