Well, the Hijri date 9 Rabi Al Thani 1400 corresponds to the Gregorian date Monday, 25 February 1980. This date lies in the fourth month of the Hijri year 1400 AH, which is Rabi Al-Thani of 1400 AH. Both this Hijri and Gregorian date occur on the single day that is Monday without any doubt. The Arabic date 1400/04/09 is calculated using the Umm Al-Qura calendar and the sighting of the moon. One thing to remember is that this Arabic date may occur on different Gregorian date depending upon the region and country and obviously the moon.
If you are still not sure about the date then you can use our Arabic date converter.
The following is the conversion of the Gregorian date 25 February 1980 to its equivalent Arabic date.
The following is the conversion of the Arabic date 9 Rabi Al Thani 1400 AH to its equivalent Gregorian date.
أَمْ حَسِبْتُمْ أَن تَدْخُلُوا۟ ٱلْجَنَّةَ وَلَمَّا يَأْتِكُم مَّثَلُ ٱلَّذِينَ خَلَوْا۟ مِن قَبْلِكُم ۖ مَّسَّتْهُمُ ٱلْبَأْسَآءُ وَٱلضَّرَّآءُ وَزُلْزِلُوا۟ حَتَّىٰ يَقُولَ ٱلرَّسُولُ وَٱلَّذِينَ ءَامَنُوا۟ مَعَهُۥ مَتَىٰ نَصْرُ ٱللَّهِ ۗ أَلَآ إِنَّ نَصْرَ ٱللَّهِ قَرِيبٌۭ
Or think ye that ye will enter paradise while yet there hath not come unto you the like of (that which came to) those who passed away before you? Affliction and adversity befell them, they were shaken as with earthquake, till the messenger (of Allah) and those who believed along with him said: When cometh Allah's help? Now surely Allah's help is nigh.
Surah Al-Baqara(2:214)