September 5, 1993 | At 9, Christian Slater made his Broadway debut, opposite Dick Van Dyke, in a revival of The Music Man. At 14, he made his movie debut as a fugitive from a Texas dragnet in The Legend of Billie Jean.  At 15, he co-starred with Sean Connery and F. Murray Abraham in The Name of the Rose. At 18, his stock soared when he came across as a younger, possibly more dangerous Jack Nicholson in the cult fave-rave, Heathers.

At 20, however, Slater was on the verge of destroying himself through substance abuse. At the height of his notoriety as a wild and crazy hellraiser, he was arrested twice for drunk driving, and placed on five years' probation.

It's an all too typical Hollywood story: Early success, quick burn-out, sudden oblivion.

Fortunately, this particular story has an atypical happy ending.

''There is that one awakening moment,'' Slater said a few days ago in his Los Angeles hotel suite, ''where you're like this speeding express train, and you go crashing into a wall. And I did have an experience like that, I suppose. And it did sort of jar me into my senses.''

If he is reluctant to be more specific, Slater is not at all hesitant to admit that, at 24, he finds ''things are for the most part much clearer now. It's much easier to deal with things.

''From the time I was 20 until now, I've changed a lot.''

And that is reflected, Slater said, in the way he behaves on the set. ''I'm not late anymore, I'm professional. I show up, I do my job. I'm together. I'm not looking to do anything too self-destructive.''

Judging from the comments made during a recent press gathering, the new and improved Christian Slater made quite an impression on his co-stars during the filming of True Romance, a darkly comical action-adventure that opens Friday.

In the film, directed by ultra-slick Tony Scott (Top Gun) from a screenplay by up-and-comer Quentin Tarantino (Reservoir Dogs), Slater is Clarence, a comic-book store clerk who tries to be a hardboiled hero when he falls for a perky young prostitute, Alabama (Patricia Arquette). During a gun battle with Alabama's vicious pimp (Gary Oldman), Clarence grabs the wrong suitcase, and winds up with a humongous amount of cocaine. So he and Alabama set out for California, where they hope to sell the merchandise to the highest bidder. This, not surprisingly, is a big mistake.

Part of the challenge in playing Clarence, Slater said, was ''to see if I could be that type of personality again and not have to be as -- well, I suppose as crazy as I used to be. Or as self-destructive. I'm glad I had Tony (Scott) there to help me along, and guide me through.''

Given Slater's well-publicized past as a self-indulgent wild man, it seems, somehow fitting that, in True Romance, he is cast as the son of another wised-up and dried-out ex-reprobate, Dennis Hopper.

 Hopper fully appreciates the irony -- and deeply respects his young co-star.

''I'm very proud of Christian,'' Hopper said during a break in his True Romance promotional chores. ''First of all, he's so young to be clean and sober. And to be in an anonymous 12-step program, and to maintain that. That's really something to be encouraged, and admired.

''Of course,'' Hopper added with a chuckle, ''I have a few more years in the program, about ten years now ... But I did a lot of drinking and drugging way into my later years, before I got the message that there was another way.''

Slater -- the very model of GQ-stylish respectability in a gray-green double-breasted suit, green shirt with white stripes, and expensive-looking brown shoes -- smiled broadly when told of Hopper's tribute.

''I was very nervous, absolutely, when I first met Dennis,'' he admitted as he reached for another Marlboro Light. ''That was like a walking living legend there... But I guess the true legends are the ones who don't act like it.''

He and Hopper work so well opposite each other on screen, Slater surmised, because ''we do have an underlying understanding of each other, I think. There is something there, where we have both gone down a certain path. For him, it may have taken a little bit longer to realize how dark it actually was. But we definitely both do have something in common with each other.''

Slater, the son of stage actor Michael Hawkins and casting director Mary Jo Slater, has been acting since he was 7 years old, when he landed his first job on the daytime TV drama One Life to Live. Two years later, he was approached by director Michael Kidd for a role in the Music Man revival.

''I was 9 years old when Michael Kidd made the call, that he wanted me to come in and audition for this musical. And my mother asked me if that's what I wanted to do. She said it was going to be a lot of work, it was going to be a hard job. And I said, 'No, absolutely, I want to do it.'

''And of course, at that time, all I saw it as was an opportunity to go away and get out of school. Then they pulled the tutors on me, and I was fooled again.''

Slater next appeared on Broadway as the doomed son of Macduff in a production of Macbeth with Nicol Williamson, yet another notorious hellraiser, in the lead role. Asked if he thought the volatile Williamson might have been a singularly bad influence for an impressionable youth, Slater smiled again, and nodded his head.

''Probably, yeah. The effects of these guys who I've worked with have been positive and devastating, all at the same time.''

High on his list of positive influences is Tony Bill, the director of Untamed Heart, who gave Slater one of his sweetest, least typical roles. In the bittersweet romantic drama, newly available on home video, Slater was cast against type as an introverted loner who slowly emerges from his shell when he falls in love with a sympathetic waitress (Marisa Tomei).

''That was definitely the smoothest, easiest film I've ever done,'' Slater said. ''And I think that stems a great deal from the character I was playing -- somebody who was so simple, and so loving, and so caring, and didn't want to hurt anybody. I just tried to adopt that kind of personality, and tried to be as loving as I possibly could, completely unselfish... And my life was extremely uncomplicated.

''But for me, I guess, that kind of consistency, I just cannot maintain it. I cannot maintain at this point in my life that type of consistent behavior. For some reason, for me, I need to mix it up a little bit.

''I said to Dennis one night, 'God, my life is just utter chaos.' And he says, 'Well, it's supposed to be. You're an actor.' And I felt much better after that.''