What number comes next 2 3 5 9?

Answer 1

Answer: 11

It's a list of prime numbers

Q:

.....since when is 9 a prime number?

Answer: 17

It's not a list of primes, it's not a Fibonacci sequence. The only pattern I see is that the last number in the sequence gets a number added to it to produce the next number in the sequence, the number that's added doubles each time. E.g. 2+1 = 3 (1 is added)

3+2 = 5 (1 is doubled = 2, then added)

5+4 = 9 (2 is doubled = 4, then added)

9+8 = 17 (4 is doubled = 8, then added)