update to mtk v9

[xtalax]

Checklist

• [ ] Appropriate tests were added
• [ ] Any code changes were done in a way that does not break public API
• [ ] All documentation related to code changes were updated
• [ ] The new code follows the contributor guidelines, in particular the SciML Style Guide and COLPRAC.
• [ ] Any new documentation only uses public API

Additional context

Add any other context about the problem here.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 84.61538% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 79.73%. Comparing base (113becf) to head (8d7c922).

:exclamation: Current head 8d7c922 differs from pull request most recent head ee9c62a. Consider uploading reports for the commit ee9c62a to get more accurate results

Files	Patch %	Lines
src/interface/solution/timedep.jl	60.00%	2 Missing :warning:
src/MOL_discretization.jl	0.00%	1 Missing :warning:
src/discretization/staggered_discretize.jl	94.73%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #380 +/- ## ========================================== - Coverage 85.28% 79.73% -5.55% ========================================== Files 41 41 Lines 1991 1979 -12 ========================================== - Hits 1698 1578 -120 - Misses 293 401 +108 ```

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