SPI clock synchronization issue and inconsistency with data output
When you send an "A" character you are not getting a value of 0x0A. Instead you are getting the binary value that corresponds to the ASCII encoding for the "A" character. The values below show the ASCII encodings for some characters:

"A" = 0x41 = 0b0100_0001
"B" = 0x42 = 0b0100_0010
"C" = 0x43 = 0b0100_0011
"D" = 0x44 = 0b0100_0100
"E" = 0x45 = 0b0100_0101
"F" = 0x46 = 0b0100_0110


If you want to send an actual value of a given binary such as 0b0000_1010 the give that value to the output routine instead. Writing the number in hexadecimal would be 0x0A.

NOTE: I have used an underscore in the binary numbers to separate the separate 4-bit nibbles to make it more readable. This would not be accepted by most compiler tools.

In your pictures the SPI mode that you have selected outputs the first data bit a half a clock time before the first emitted clock. You may want to experiment with choosing the various modes available and seeing what they look like on the scope. This will help you to better understand the positioning of the data bits with respect to the clock.