To solve this 9-digit difference number puzzle, we need to find a number that satisfies the following conditions:

1. The 9-digit number is split into three 3-digit segments, let's call them $ABC$, $DEF$, and $GHI$.
2. The difference between the first three digits (ABC) and the second three digits (DEF) must equal the third set of three digits (GHI).
3. Each digit from 0 to 9 is used exactly once across the 9-digit number.

Let's break down the approach to solving this problem:

1. Define Variables:

   • Let $ABC$, $DEF$, and $GHI$ represent the three 3-digit numbers.
   • Mathematically, this can be expressed as: $ABC - DEF = GHI$

2. Constraints on Digits:

   • Since we must use each digit from 0 to 9 exactly once, the numbers $ABC$, $DEF$, and $GHI$ will each be unique 3-digit numbers composed of these digits.

3. Solution Strategy:

   • We could start by trying various values for $ABC$, $DEF$, and compute $GHI$ to see if it fits the criteria (being a unique 3-digit number and using the remaining digits).
   • To simplify this task, a systematic or algorithmic approach would help, potentially leveraging trial and error or programming to verify combinations.

Given the constraints, would you like me to attempt to find a solution manually with a systematic approach or would you prefer I use a computational method to iterate over possible values? Alternatively, I can provide hints on how you might set this up programmatically if you'd like to explore it yourself!