Op amp as a Schmitt trigger
Few thoughts.
Check your connection to ground as peter Bennett mentioned.

Second Issue is that your op-amp cant run close to the ground rail as Kevin White mentioned. Look up common mode input range. Your input is running at 1.8 V where as you can only go down to about 3V on the inputs according to the data sheet assuming a +-15v supply it can go +- 12 (VICR "Common mode input range"). It will behave similarly at 9 Volts. This effectively leaves your operating area on the inputs between 3V and 6V on this op-amp. Where as you are running the op-amp at 1.8 volts on the input. 

If this is the problem, the solution would be to find an op-amp that can go down to 1.8 volts and lower on the inputs or to change your dividers. Where 8k and 2k resistors changed to 5k on the Vin-. And the 10K going to 1k and 5k going to 9k on Vin+. This would let the operating voltage of the input be 4.5 with an output of 5V.