Based on the iFixit tear-down of the Samsung Galaxy S9 you can see that the flash chip in this model is a single chip soldered onto the motherboard - it is inside the orange rectangle below, a 64 GB UFS (NAND flash + controller):
Therefore theoretically it may be possible to unsolder this chip and read out the content if you manage to get the chip working in a different environment.
However even if you manage to read out the chip completely it may be of no use as usually Android devices come with enabled encryption by default (not sure about Samsung and especially this device). The encryption method uses hardware based cryptography, which means that the key is not directly stored in the flash chip but requires other system components like the CPU. However I don't know the exact details on the used encryption especially where the keys protected by the "Hardware Security System" are actually stored.
As your device most likely uses File based Encryption (FBE) there may be some files accessible that are unencrypted, however I don't have any experience what files are typically stored without encryption. My assumption is that most of the app/usre data is encrypted.