You can suppress floats but then allow them after the 9th page.
aaa \newpage aaa \newpage aaa \newpage aaa \newpage aaa \newpage aaa
The package ragged2e provides the environment justify, which should be used as
within a left- or right-flushed text. Like all environments, internally it is implemented by two macros \justify and \endjustify, which explains why using \justify in your example does not lead to obvious (La)TeX errors but to a messed output.
You may want to pass the openany option to the book document class:
book defaults to starting new chapters on right (odd) pages, i.e. openright, but you can change this by passing openany (it's just the other way around for report, BTW).
It depends on what your toc looks like exactly, but in general I would suggest playing around with the spacing inside the toc rather than shifting the whole thing.
Since you are using scrartcl you don't need the tocloft package for adjustments to the TOC. For example, you could change the beforeskip value for section entries to fit the table on one page by ...