After releasing Android 9 Pie for the American Galaxy S9, S9+, and Note 9, Samsung is now rolling out the new software to the US variants of the Galaxy S8, S8+, and Note 8. People in other countries, such as the UK, India, and Korea, were already able to participate in the beta program, and it only made sense for the 2017 handsets to follow in their siblings' footsteps.
To sign up for the beta program, you need to install Samsung+ and head over to the Notices section. Once you've enrolled, you should be prompted to download the latest software through an OTA update. After this process, Galaxy S8, S8+, and Note 8 devices will run firmware versions G950U1UEU5ZSAB, G955U1UEU5ZSAB, and N950U1UEU5ZSAB, respectively. Bear in mind only unlocked phones, i.e., model numbers SM-G950U1, SM-G955U1, and SM-N950U1, are eligible for the beta program in the US.
This update brings all the benefits of Android 9 Pie, One UI, and the January security patch in a single package. As this is still beta software, you should expect to experience some bugs, with the tradeoff of getting early access to Samsung's new interface. In case you'd rather wait for a stable release, the Note 8 is expected to receive it in February, while the S8 and S8+ will receive it a month later.