Dictionary.com licenses the resultative meaning ['and therefore'] of and so:

In formal English, so is not used as a conjunction, to indicate either purpose (he left by a back door so he could avoid photographers) or result (the project was abandoned so his services were no longer needed). In the former case to or in order to should be used instead, and in the latter case and so or and therefore would be more acceptable.

• [the project was abandoned and so his services were no longer needed].

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It also licenses the independent–clause-initial use of so (for sentences; this must allow for the use after semicolons):

Like and, but, and or, so can occur as a transitional word at the beginning of a sentence:

• So all our hard work finally brought results.

Dictionary.com licenses the resultative meaning ['and therefore'] of and so (though not the use of so itself as a coordinator in formal registers):

In formal English, so is not used as a conjunction, to indicate either purpose (he left by a back door so he could avoid photographers) or result (the project was abandoned so his services were no longer needed). In the former case to or in order to should be used instead, and in the latter case and so or and therefore would be more acceptable.        [Hence     •The project was abandoned and so his services were no longer needed].

.........

It also licenses the independent–clause-initial use of so (for sentences; this must allow for the use after semicolons):

Like and, but, and or, so can occur as a transitional word at the beginning of a sentence:

• So all our hard work finally brought results.

Stylewise, though, I'd personally avoid the semicolon usage as rather ugly. A comma, or a dash/ellipsis to signal a longer dramatic pause, in informal registers, or 'and so' in formal ones.