Juveniles

Robert Heinlein is rightly respected for most of his juvenile sf novels - all twelve of the Scribner ones. Five of these form a Juvenile Future History, in my opinion. They are consistent with the "Green Hills of Earth" period of the (adult) Future History.

A few instalments of Poul Anderson's Technic History were written and published for a younger audience - also possibly one instalment of his Time Patrol series. Also in the Technic History, Christopher Holm and Diana Crowfeather strike me as perfect Heinleinian juvenile heroes. Crucially, both are able to assert their independence. On the eve of war, Christopher/Arinnian bids a hasty goodbye to his father on the phone screen, does not have time to visit his mother and flies by antigrav belt to where he wants to be, a household of the Stormgate Choth where he eats in a dining hall and meets his friend, Eyath, a young female Ythrian. Diana runs away from home rather than attend Navy school and marry an officer while:

"...Tigeries were hunting through hills where wind soughed in waves across forests, and surf burst under three moons upon virgin islands."

-Poul Anderson, The Game Of Empire IN Anderson, Flandry's Legacy (Riverdale, NY, June 2012), pp. 189-453 AT CHAPTER ONE, p. 214.

She sleeps in a "...ruinous temple..." (p. 196) which is surely very Heinlein and Kipling.

Arinnian and Diana cannot meet because they live in very different periods of the Imperial era.