STM32 ADC initialization without HAL - stm32

Question

I'm trying to write some basic code without HAL to initialize and read from an ADC, but I can't get it respond properly. I'm using an STM32F103C8T6 on a blue pill dev board. Function is the following:
Pin B1 (ADC9) is connected to a 0-3.3V signal (a 12V supply voltage through a voltage divider)
When the signal goes below a constant that i've called SUPP_V_MIN_VAL, pin B9 is set. If the signal is above that value, pin B9 is cleared.
I defined SUPP_V_MIN_VAL to be 2606.0. I am casting everything as a float because, in a separate section in my code, i need to display the current ADC value as a float).
The issue is that I think I am not initializing my ADC properly, or not casting my types properly. I'm finding that the ADC reading is always 0. My initialization is below:
RCC->APB2ENR |= 0x1UL << 3; //Initialize clock for GPIOB (bit 3), if it hasn't been initialized yet
RCC->APB2ENR |= 0x1UL << 9; //Initialize clock for ADC1 (bit 9), if it hasn't been initialized yet
GPIOB->CRL &= ~(0xF0UL); //SetBar pin PB1 to analog input
//ADC1->CR1 |= 0x0UL; //Default settings are correct - ignore
ADC1->CR2 |= 0x2UL; //Enable ADC1_CR2_CONT for continuous conversion
//ADC1->SMPR1; //ADC channels in SMPR1 are not used - ignore
ADC1->SMPR2 |= 0x38000000UL; // Set SMP9 to 239.5 cycles (set bits 27-29 to 1)
ADC1->CR2 |= 0x1UL; //Set CR2_ADON to wake up ADC from sleep mode
ADC1->CR2 |= 0x1UL << 3; //Initialize calibration register
while ((ADC1->CR2 >> 3) & 0x1UL); //Wait until calibration register is initialized
ADC1->CR2 |= 0x1UL << 2; //Enable calibration
while ((ADC1->CR2 >> 2) & 0x1UL); //Wait until calibration completed
ADC1->CR2 |= 0x1UL; //Set CR2_ADON again to turn on ADC and start converting
I am reading the pin with:
void pollSUPP(void)
{
uint16_t ADC_Reading = ADC1->DR;
suppVolt.float_var = (float) ADC_Reading;
if( suppVolt.float_var < SUPP_V_MIN_VAL)
{
// digitalWrite(SUPP_LOW, HIGH); PB9
GPIOB->BSRR = 0X1 << 9;
}
else {
GPIOB->BRR = 0X1 << 9;
}
}
SuppVolt is defined as
union {
float float_var;
uint8_t chars[4];
} suppVolt; //ADC reading for supply voltage
I may also be doing something stupid (I haven't actually confirmed that Pin B9 is on ADC1, but I am assuming it is since the blue pill only has one ADC??) or referencing the wrong bit in a register.
Can anyone help me spot my error? Thank you in advance!!