Using Extented Licence on POD Sites Such As RedBubble

I think so. You can sell prints of an asset, and I can't see, how print on demand should be different. However, you can't offer the asset to be downloaded.

Look here for more information on licensing: https://community.adobe.com/t5/stock/links-for-licensing-terms/td-p/11366788
(Disclaimer: As always with licensing, this is my interpretation of the rules. I think they are correct and advice is based on reading and interpreting the licence terms and on fair use for both the buyer and the artist/stock company, but I cannot rule out that my interpretation is wrong. I'm not an Adobe employee).