Identify a young adult novel involving gates or bridges and a troubled boy

Question

Here are all the details I remember. I read the book in the 90's. The cover may have involved an archway?

The title could have been "Seven/Nine gates to _____." but honestly not sure.

The story centers on a girl who finds a portal to another realm (One was located under a bridge?). She meets a troubled boy from school and realizes that the world is his creation to escape an abusive father. I remember that they found a pocket watch that had significant meaning to him and was used as the magic weapon to destroy the villain (his father?).

There may also have been something to do with him bleeding and a rose. Vague I know, but it has been eating at me for two decades.

Answer 1

I found the following which matches the title somewhat, but the description doesn't seem to match with what you have described.

The Seven Gates of Time by Gary Wilkes.

High School is out for summer break and Garret Walker is thinking of his summer job, time with friends, and especially his chance of a first date with Elsa Cooper. His Friday’s date incurs some displeasure when, Elsa’s cousin Celia Barns and her family show up to visit the Cooper’s.Elsa asks Garret if it’s okay that Celia tags along on their date. Garret attempts to enlist his friend, Serge Ramirez, to join them as a companion for Celia. Serge had already made plans for the night with another of their friends, ...