In this problem, the symbol $0$ represents the number zero, the symbol $1$ represents the number seven, the symbol $2$ represents the number five, the symbol $3$ represents the number three, the symbol $4$ represents the number four, the symbol $5$ represents the number two, the symbol $6$ represents the number nine, the symbol $7$ represents the number one, the symbol $8$ represents an arbitrarily large positive integer, the symbol $9$ represents the number six, and the symbol $\infty$ represents the number eight. Compute the value of $\left|0-1+2-3^4-5+6-7^8\times9-\infty\right|$.

[i]2016 CCA Math Bonanza Lightning #5.2[/i]
1. First, we need to replace each symbol with its corresponding number:
   \[
   \left|0 - 1 + 2 - 3^4 - 5 + 6 - 7^8 \times 9 - \infty\right|
   \]
   becomes
   \[
   \left|0 - 7 + 5 - 3^4 - 2 + 9 - 1^8 \times 6 - 8\right|
   \]

2. Simplify the expression step-by-step:
   \[
   0 - 7 = -7
   \]
   \[
   -7 + 5 = -2
   \]
   \[
   3^4 = 81
   \]
   \[
   -2 - 81 = -83
   \]
   \[
   -83 - 2 = -85
   \]
   \[
   -85 + 9 = -76
   \]
   \[
   1^8 = 1
   \]
   \[
   1 \times 6 = 6
   \]
   \[
   -76 - 6 = -82
   \]
   \[
   -82 - 8 = -90
   \]

3. Finally, take the absolute value:
   \[
   \left|-90\right| = 90
   \]

The final answer is \(\boxed{90}\).