Series Connected Secondary Transformer
I'm wondering if it's safe to assume that by connecting the pair 9-13
  in series with 2-18 I could expect to get a 24VAC. The same for 9-14
  with 2-19 which should give a 30VAC.


I think it's a safe bet that if you series connected the windings you get twice the voltage so, for instance 9-13 in series with 2-18 would give you 24 V AC. Ditto for 9-14 and 2-19 to give 30 V AC.


  It is safe to assume that by connecting the pin 9 to 13 then 13 to pin
  2 I would get a 24VAC between pins 9-18 ?


You cannot connect pin 9 to pin 13 under any circumstances (unless you want to burn out a winding).