How to go to Shaolin temple from the Longmen grottoes?and how long it takes?

I remember there are two direct buses between the two destinations, leaving the grottoes at 10:30 and 15:30. So you can consult whether they are in operation or not.

The second option for you is to take bus no. 81 to Luoyang Railway Station, near which you can take a direct tourism bus to the Temple. The whole journey takes aorund 2.5h.

Do anyone know if those buses are still available on 2019?? thanks for the help

Yes, they are available.