Okay, that's 9 LED's -- you'll probably need at least a ULN2803 Darlington Array to drive that much current, the BS2 won't do it on its own.
And you'd probably want a 74LS164 serial to parallel latch to reduce the number of I/O pins needed.
If you limit the current to each LED to something on the order of 4mA using a 1K series resistor, you can drive the LEDs directly using 9 I/O pins. The "What's a Microcontroller?" tutorial shows how to connect a single LED to an I/O pin.
You can also drive the LEDs as a multiplexed matrix where you drive only one LED at a time, but use more current and drive them fast enough so that "persistence of vision" takes place and it looks like several LEDs are on at the same time.
bs2-man
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And you'd probably want a 74LS164 serial to parallel latch to reduce the number of I/O pins needed.
You can also drive the LEDs as a multiplexed matrix where you drive only one LED at a time, but use more current and drive them fast enough so that "persistence of vision" takes place and it looks like several LEDs are on at the same time.