Since your contraceptive device had shifted out of position by the time of intercourse on September 13th, it may not have given you full protection that cycle. This means a pregnancy is possible, though it isn't certain.
Next Steps
A home urine
pregnancy test about three weeks after September 13th will give you a clear answer. An earlier blood test can also confirm it if you'd rather not wait that long. Please share this timeline with your gynaecologist at your follow-up.
Health Tips
If your period doesn't arrive as expected, please see your gynaecologist without delay. The same goes for any new pain or unusual bleeding.