Welcome to the Magix Sound Forge users forum @MIKE-HAYTER.

I am not sure I understand your query.
Do have have Sound forge 9.0 installed but do not have the activations serial code?
The 'Audio Studio' named versions of Sound Forge started with Sound Forge 10. There was a lite version of SF-9, I think it was named Sound Forge-9 LE .

In any case you cannot get a 'new' serial code for a previously registered product.. However, you should be able to look it up in "Magix Service Center> My Products", or in the SCS (Sony) archives. Either-way you will at least need the email address you usedwhen it was originally registered and activated.

Or.. are trying to get the latest of Sound Forge? (Audio Studio or Pro 15), which you would have to purchase. You are eligible for a discounted upgrade price, but you will still need the Sound Forge-9 serial code and your original email address for verification.