Have you used any special or unique methods to derive your 8~9character password from the 15characters?
If yes, then it wont be possible without knowing the exact method that you've used.

Or have you picked random 8 or 9 characters from those 15 without using duplicate?
If yes, bruteforcing an 8~9 character password with BTCRecover from 15 characters is quite doable with roughly, ¹⁵P₈ plus ¹⁵P₉ maximum number of combinations.
But you need a fast processor for this since it may take months with old generation processors, plus it wont work with GPU.

For the setup, read through the updated version's official documentation: https://btcrecover.readthedocs.io/en/latest/INSTALL/
Then, the usage: https://btcrecover.readthedocs.io/en/latest/TUTORIAL/
(DYOR since it has all the info you need)

And here's a short guide for your case:

• Your "tokens.txt" should compose of your 15 character long password, one character per line.
• You would need to add --length-min 8 --length-max 9 to specify that your password can only be 8~9characters long.
• Due to the billions of possible number of combination, you may have to add --no-eta -d to skip the initial password counting procedure.

Here's an example command:

I think you can still able to revive your SSD if it is just corrupted or undetectable you can try the power cycle method because SSD has a self-repair feature to fix corrupted and undetectable issue. Check the guide here
I have experience with my Samsung SSD before it was undetectable on Windows even on the BIOS I just repaired the SSD through the power cycle method.
So try this it might be also work in your SSD if it does not work try to resolder the SSD terminals.

If it still does not work you don't have any other choice but to use the service provided above or brute-force the wallet file using the BTCrecovery tool.