Configure Serial with registers on STM32l073RZ
There are a few apparent problems


TX pin is not configured for the serial port, presumably it's still in analog mode after reset. You should set it to alternate function mode in GPIOA-&gt;MODER, and assign it to USART1 in GPIOA-&gt;AFRH. The alternate function numbers are listed in the datasheet, not in the reference manual.
You should check USART_ISR_TXE each time before writing to TDR, waiting until it becomes 1.
while (!(USART1-&gt;ISR &amp; (USART1-&gt;ISR | USART_ISR_TXE)));


This expression is nonsense.


GPIOA-&gt;ODR |= GPIO_ODR_OD9;


This is unnecessary. Setting ODR has no effect unless the pin is set as output.