Note that premium economy is an entirely new product, rather than simply a rebranding of Main Cabin Extra, which will still be available. Premium economy seats are wider and include additional legroom, and adjustable foot, leg and head rests. Passengers will receive noise-canceling headphones, amenity kits, improved meals and more. You can see a full list of perks here.

Officially, these new flights go on sale beginning July 10, however it appears that you can book both routes as of today, since American already operates both flights with the 777. Presumably, if you book today for travel on or after November 4, you'll be flying the 787-9 even though you'll see 777 or 77W listed for the time being.
Here's the inaugural 787-9 flight to Madrid:

And here's the first Dreamliner flight to Sao Paulo:

Interestingly, AA won't begin selling premium economy seats until early 2017. American will be making the new product available to "select customers" prior to its official launch — while it's not clear what the criteria will be, it seems likely that these seats will be available to top elites.
In addition to 21 premium economy seats in a 2-3-2 configuration, each 787-9 will offer 30 lie-flat 1-2-1 biz seats, 27 Main Cabin Extra seats with six extra inches of legroom and 207 economy seats, both in a 3-3-3 configuration. AA's latest Dreamliners will also offer Wi-Fi, on-demand video with nearly 300 movies and the standard 787 dimmable windows.
Will you be booking AA's new premium economy product?










