x8 + x2 + x1 + x0
In binary, X is 2.
So the polynomial translates to:
28 + 22 + 21 + 20
Which equates to, in binary:
876543210
100000111
However, the first bit is omitted - so it becomes:
76543210
00000111
Or 0x07 in hexadecimal.
This is the CCITT CRC-8 code. (9 bits). There are other variants.
The Wikipedia page on CRC's has information in implementing it: Cyclic redundancy check - Wikipedia
You apply the CRC code to the left-most chunk of your data, then slide it along the result 1 bit. Repeat, until you reach the end.