TPS92661-Q1: TPS92661 drive inquiry

Dear TI,

I have a question about driving the TPS92661.

1. With regard to IC Initialize, it is planned to operate at a baud rate of 500kbps by applying 8MHz through the PIC IC to the CLK pin.
Are you ready for communication with a square wave on the CLK pin without setting it up?

2. In order to modify one register in data transmission, five bytes are transmitted,
To turn LED1 ~ LED9 on or off at once, 5 * 9 = 45. Or is there a way to simplify it?

3. In addition, how to write about data writing method when writing data to register. How do I set each digit value for 8 bits?
Ex 1) If you try to turn ON LED1ONL until OFF command is given, if data is given as 0xff,
        LED1 is on until LED1OFFL reaches 0xff? Or is it possible to toggle only certain bits?
Ex 2) If LED1_4ONH turns on LED1 ~ 3 and LED4 turns off, does it become 0x3f?

Thank you.