
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Let $f(x)$ be an increasing function defined on $(-1,+\infty)$, and $f(xy)=f(x)+f(y)$. If $f(3)=1$ and $f(a) > f(a-1)+2$, find:
(1) The value of $f(9)$,
(2) The range of $a$.

Present the answer in LaTex format: \boxed{Your answer}
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