2nd grade number patterns

Question

Number Series
I am having problems with these 2

3 2 6 4 9 6 12 8 (what should be next?)
3 6 9 12 9 6 3 6 (what should be next?)

Answer 1

15
12

Answer 2

I know the top one is 15 because is goes 3 then 2 down then add 3 to the previous number(3) so that's 6 then 2 down etc.

for the second one i don't think its 12 i think its 9 because it goes up from 3 to 12 then starts counting down then when it gets to 3 it counts up again so the next one after 6 would be 9 :)