Hi,
From the pinmux spreadsheet, you can find that the complete pin name of GPIO09 is CAN1_STB.
It’s stated in page 6382 and 6382 in TRM, named PADCTL_AO_HV_CAN1_STB_0, and with an offset of 0x40.
From page 6085, you can see the base address block of AO_HV is PADCTL_A15.
Finally, you can see from page 73 that the base address of PADCTL_A15 is 0x0c303000, so you have 0x0c303000 + 0x40 = 0x0c303040