Hi Tsui!
Thank you for bringing your question to the Disney Parks Moms Panel!
Disney's Polynesian Resort and Village is such a beautifully themed resort. I love being able to hop on the monorail to head into
Magic Kingdom Park!
In theory, the bus from Magic Kingdom straight to
Disney's Animal Kingdom Theme Park would be quicker and one less step than going back to the Polynesian Resort and taking a bus. However, since it will be early in the morning, there may be more buses running from the resorts to the parks than running between the parks.
I suggest asking a Cast Member working in front of Magic Kingdom Park how often buses are running between the parks that early. They can give you a guideline on how long to expect to wait for the bus to Animal Kingdom.
An option that would be quicker than taking the monorail back to the Polynesian, would be to walk the path to
Disney's Contemporary Resort and take the bus from there. The walk from Magic Kingdom to the Contemporary would be about ten minutes. If walking isn't ideal, you could also take the resort monorail and get off at the Contemporary since it's the first stop.
I hope this helps! Please let me know if you have any other questions.
~Lori