I need help designing a circuit which will act as a buffer (or voltage follower) and also an other circuit which will act as an amplifier ( lets say X10 linear gain). Both must work well for a frequency between 30Hz and 10kHz. they must be single supply, (+9V/GND).

thanks in advnced

 

Any half-decent transistor or Jfet makes a voltage follower good to 100 MHz.
The value of the coupling capacitors and impedances determines the low frequency cutoff.
10x gain is simple. Single supply is also simple.