Help needed: Setting UART pins on Pico W

[XeYaRiQu]

Hi all, I am new to MP and RPi in general so I apologise in advance if my question seems elementary.

I am trying to grab/send data from a FlySky receiver using UART1 on GP8 and GP9 of the Pico W. I have modified some code I obtained from penguintutor for the iBUS protocol.

class IBus ():

    # Number of channels (FS-iA6B has 6)
    def __init__(self, uart_num, baud=115200, num_channels=6):
        self.uart_num = uart_num
        self.baud = baud
        self.uart = UART(self.uart_num, self.baud, rx=Pin(9), tx=Pin(8))
        self.num_channels = num_channels
        # ch is channel value
        self.ch = []
        # Set channel values to 0
        for i in range (self.num_channels+1):
            self.ch.append(0)
            
            
    # Returns list with raw data
    def read(self):
        # Max 10 attempts to read
        for z in range(10):
            buffer = bytearray (31)
            char = self.uart.read(1)
            # check for 0x20
            if char == b'\x20':
                # read rest of string into buffer
                self.uart.readinto(buffer)
                checksum = 0xffdf # 0xffff - 0x20
                # check checksum
                for i in range(29):
                    checksum -= buffer[i]
                if checksum == (buffer[30] << 8) | buffer[29]:
                    # buffer[0] = 0x40
                    self.ch[0] = 1 # status 1 = success
                    for i in range (1, self.num_channels + 1):
                        self.ch[i] = (buffer[(i*2)-1] + (buffer[i*2] << 8))                    
                    return self.ch
                else:
                    # Checksum error
                    self.ch[0] = -2
            else:
                self.ch[0] = -1
                
        # Reach here then timed out
        self.ch[0] = -1
        return self.ch
    
    
    # Convert to meaningful values - eg. -100 to 100
    # Typical use for FS-iA6B
    # channel 1 to 4 use type="default" provides result from -100 to +100 (0 in centre)
    # channel 5 & 6 are dials type="dial" provides result from 0 to 100 
    # Note approx depends upon calibration etc.
    @staticmethod
    def normalize (value, type="default"):
        if (type == "dial"):
            return ((value - 1000) / 10)
        else:
            return ((value - 1500) / 5)

ibus_in = IBus(1)

while True:
    data = ibus_in.read()
    # if signal then display immediately
    if (data[0]):
        print ("Ch.1: {:<6}  Ch.2 {:<6}  Ch.3 {:<6}  Ch.4 {:<6}  Ch.5 {:<6}  Ch.6 {:<6}".format(
            IBus.normalize(data[1]),
            IBus.normalize(data[2]),
            IBus.normalize(data[3]),
            IBus.normalize(data[4]),
            IBus.normalize(data[5], type="dial"),
            IBus.normalize(data[6], type="dial"),
            end=""))
    elif data[0] == -1:
        print("No packet")
    else:
        print("Bad packet")

When I wire up the receiver to GP9, I do not receive anything but when wiring up to GP5, I am able to obtain the data even though I specified rx=Pin(9).

Additional information:
I am using VS Code with the MP extension and the Pico is connected to my PC via a micro USB cable. I am running the code without uploading to the Pico.

[XeYaRiQu]

Looking at https://github.com/raspberrypi/pico-sdk/blob/6a7db34ff63345a7badec79ebea3aaef1712f374/src/boards/include/boards/pico_w.h and the pinout diagram I see that UART0 defaults to GP0 and GP1, but I do not see any defined for UART1. When I do not specify any pin in the uart object, I expect to not receive any data on any UART1-capable pins but I observed that GP5 is still able to receive the packets. Is there something I am missing out on?

from machine import Pin, UART

uart0 = UART(0)
uart0.init(tx=Pin(12), rx=Pin(13))
uart1 = UART(1)
uart1.init(tx=Pin(8), rx=Pin(9))

print("Writing 'Test' from UART0 to UART1")

uart0.write('Test 1')
uart0.txdone()

print("Reading UART1")
print(uart1.read()))

Tried the above with 2 wires connecting GP0 to GP5 and GP1 to GP4. Have resetted my Pico but am still able to send and receive data on UART0 and UART1.