Yahoo! does not offer a whitelist, but they do have a program where high volume senders can submit their IP addresses for review. Based on the review, Yahoo! will modify your reputation in their system if it is appropriate. It is important to note that an IP address reputation modification by Yahoo! does not guarantee inbox placement.
How to submit your IP addresses for review
If you are a new sender or have a new IP address, Yahoo! asks that you submit an application using the Case Creation form. This page requires that you have a Yahoo! login to access. You should be able to use the same login name and password that you used to set up the Yahoo! feedback loop.
If you are submitting an existing IP address for review, login and fill out the Case Creation form. Yahoo will contact you once they have reviewed your IP addresses, although they may not share the specifics of their investigation.