Depois de pesquisar sobre "cinderella city" e viagens no tempo, acho que provavelmente The Danger Quocient por Annabel e Edgar Johnson. Esta edição tinha uma capa verde e preta:
A pesquisa por várias frases no google books gera dois snippets relevantes de p. 114 de Ficção científica para jovens leitores , primeiro este:
Let us look at the three texts in more detail. Danger Quotient, by Annabel and Edgar Johnson, is a light atomic adventure novel for teenagers, with a slight romantic subplot. Set in the year 2127, 130 years after World War III, it depicts survivors who "live like earthworms" (4) in an underground complex in Colorado.
E então este:
He discovers his previous existence in the twentieth century as the multimillionaire Midas Forsythe, a developer who transformed Cinderella City, an enormous Donald Trumpish shopping mall
E outras pesquisas no Google Livros fornecem alguns trechos relevantes do livro Seniorplots: um guia de conversas em livros para uso com leitores com idades entre 15 e 18 anos, que esse "Midas Forsythe" criou o complexo subterrâneo no Colorado. É onde ficava a cidade de Cinderela, então, embora os trechos que encontrei não o declarem, colocando dois e dois juntos, imagino que o complexo tenha sido construído na área da antiga cidade de Cinderela:
Radioactivity has doomed them to a highly computerized, well- regulated subterranean life in a complex that had been built more than 130 years ago before World War III by a mysterious visionary named Midas Forsythe. His uncanny foretelling of the catastrophe to come led him to build an underground community equipped with the latest technology, where he, his family, and world prominent scientists were able to escape the total destruction of the world and preserve the human species.
E um dos comentários sobre a amazon menciona que o personagem principal viaja de volta no tempo:
The Danger Quotient by Edgar and Annabel Johnson. (Experiment Number 4(SCI) ) is 18, in a post-apocalyptic underground city where he and other genius "superkids" were created to rebuild the earth's ravaged ozone layer (destroyed in World War Three). Here people die in their thirties or even younger with symptoms of old age. A maverick, he instead uses a time machine created by his dead "big sister" to search for clues as to how people in the past managed to live so long. After a meeting with a street-smart young girl and her uncle in 1981 who give him the name 'Casey', he is sent bouncing around history, learning to care about people who treat him with the love he never got as an experimental child...
Aqui é outro resumo da trama:
Casey is eighteen years old in a post-nuclear world - where twenty is old age. Casey's real name is K/C-4(SCI). He's a supergenius, created in a test tube from the best genetic material available. He lives in an underground complex under what was once Colorado, along with other survivors of World War III. The colony's population is slowly dwindling. Casey himself is eighteen, and aging fast. According to the best calculations, he will die in exactly eight months and fourteen days. But why? Casey thinks the answer lies somewhere in the past, and he builds a time machine to take him there. The risks of time travel are enormous, yet Casey can't help himself. He becomes involved in the fate of a twentieth-century family, and with one girl in particular. It soon becomes clear that the future of Casey's colony depends entirely on the decisions he makes.