max. paper weight: 9010e = 200 g/m² / 9012e = 280 g/m², otherwise I have not seen any differences.

I had exactly the same question and asked HP about it.
Technically speaking, there should be no difference between the models 9010e and 9012e.
The "e" stands for HP Plus. This apparently means an additional year of warranty and 6 months of free Instant Ink and access to the HP Smart App. This is probably only if you buy it directly from HP.