Here is a portion of scripture that I think is very appropriate for 9/11.

Psalm 27

1 The LORD is my light and my salvation—
whom shall I fear?
The LORD is the stronghold of my life—
of whom shall I be afraid?

2 When evil men advance against me
to devour my flesh, ^[a]
when my enemies and my foes attack me,
they will stumble and fall.

3 Though an army besiege me,
my heart will not fear;
though war break out against me,
even then will I be confident.