Greetings Cynthia Thais, and welcome to the Disney Parks Moms Panel! I am always thrilled to answer a question from a fellow Brazilian!
Stroller rentals are available at all four theme parks, but these must be returned as you exit at the end of the day. You can also rent from Disney Featured Providers and this way take your stroller with you everywhere you go throughout the Walt Disney World Resort.
Keep in mind though, that maximum capacity for double strollers is 100 pounds for those you rent at the theme parks and also from Disney Featured Providers. Since your twins are 8-years-old and their weight combined is over 100 pounds, I suggest renting one for each boy. Some single strollers from Disney Featured Providers have a maximum capacity of 70 pounds, so your children will be more comfortable. These providers offer very convenient service. You can rent online and they deliver your stroller - and rain cover - to your hotel. At the end of your visit they will also pick it up for you.
I know that it might not be ideal to rent two strollers, but considering capacity and comfort, this may be the best option for your family. I also have friends who rent only one single stroller and their kids take turns resting. You know your children, what their habits are and how much walking they can do during the day. Families from Brazil usually stay all day long at the parks, so you need to decide based on your experience. My daughter is 6-years-old and tires easily so a stroller is always a must, especially when returning to our Disney Resort hotel in the evening.
Thanks for bringing your question to us, Cynthia Thais. Stop by the
Disney Parks Moms Panel in Portuguese next time. I will be delighted to assist you in our own language.
See ya real soon!
Thiana