I think you're looking for something like this:
func _ready():
print(is_bit_set(9, 1))
print(is_bit_set(9, 2))
print(is_bit_set(9, 3))
print(is_bit_set(9, 4))
func is_bit_set(value, bit):
return (value & (1 << (bit - 1))) > 0
Output:
True
False
False
True