To make things easier to understand we’re going to talk about the two features as a start and then we’re going to discuss the little differences in both phones you, so everything would be more clear for you!
Samsung Note9
The phone got out on August,2018
Android 8.0 (Oreo)
with a big screen of a 6.4 inches, 1440 x 2960 Pixels, 18.5:9 ratio
8GB for the Rams Exynos 9810Octa and 512GB for the inner storage
Battery capacity of 4000mAh
Camera of 12MP
Samsung S9+
Went out on March, 2018
Android 8.0 (Oreo)
the screen is 6.2 inches big and 1440 x 2960 Pixels with 18.5:9 ratio
6GB RAM Exynos 9810 Octa and 64/128/256 GB storage
Battery Capacity of 3500mAh


- 6.4-inch, 18.5:9 aspect ratio, Super AMOLED, 1440 x 2960 pixels (516 ppi pixel density), 83.4% screen-to-body ratio, HDR10 compliant, Corning Gorilla Glass 5
S9 Plus:
- 6.2-inch, 18.5:9 aspect ratio, Super AMOLED, 1440 x 2960 pixels (529 ppi), 84.2% screen-to-body ratio, HDR10 compliant, Corning Gorilla Glass 5
Battery Life:
Samsung note9 wins
as the s9+ 3500mAh
Note9 has 4000mAh for the battery capacity
Moreover both are quick wireless charging