Anything that you did using ot of date strips is useless.
If they're out of date they could be 10 pts under, or 5pts over.
If you are worried about the possibility of diabetes, get yourself a new set of strips, and do a fasting test as soon as you wake up. That should be below 6.
Since you've had GD with your previous pregnancies, it might be worth going to your GP to ask about a Hba1c test every year / 6 months or so.
This teat measures an average of your glucose levels over the last 90 days.
A reading of 9.2 after a high carb meal isn't anything to worry about.
According to the WHO Diabetes is likely if you have a reading over 10, or 11 from a capillary (finger).
Other things can cause a raise n Blood Glucose levels too. Bottom line, if you're at all worried, see a GP. They don't just drink at college... Honestly.