There are projects that are trivial in Scratch that are hard in Racket, and vice versa. Porting your Scratch projects to Racket is not likely to be a very productive use of your time because they have such different strengths and weaknesses. I think your best bet is to pick some projects which are in Racket's world teachpack's "sweet spot" and work on those with your son. <br>
<br>Don't worry about trying to "replace" Scratch with Racket. My son is a fairly sophisticated Racketeer at this point but he still has loads of fun playing around with Scratch, using it for the things it is especially well-suited for and deeply enjoying its community aspects. There's nothing wrong with appreciating both.<br>