Check the STM32L011E4Y6TR peripheral circuit.

[Tom.1]

Is it a problem to set the constant of the external pull-up resistor connected to the "PB9_Boot0" signal to 100kΩ? (R13)

Also, if there is a problem with the connection, I would like you to point out the relevant part.

[Imen.D]

Hello @田�?� 智之​ and welcome to the Community :)

BOOT0/PB9 pin limitation: typical input leakage current = 2 µA and input frequency limited to 10 kHz (1.65 V < VDD < 2.7 V) and 5 MHz (2.7 V < VDD < 3.6 V).

I advise you to refer to RM0377 and the STM32L011x3/4 datasheet for more details about the electrical characteristics of the pull-up resistors. 

Check also the STM32L011xx/L021xx device errata, if you have same conditions.

Imen