If tsh is 4, 83 and ft4 - is 9 : does it mean underactive thyiroid - hypothirodism? should i take medicine for hypothyrodism with these results?

It might ,,: This could mean hypothyroid as the TSH is high normal to high and the ft4 seems low normal. However it's also the symptoms that determine the need for meds along with the lab values and unless you've got the symptoms of hypo thyroid like fatigue, weight gain, and sensitivity to cold it's wise to hold off on meds. You can also see your doctor for further evaluation and counseling. Good luck.