I cant say much about the semantics of until in the context that you have described it as neither English nor Italian are my native languages.
However I believe that the use of until and unless and the likes are dangerous for precisely this reason. I find it far better to use while( ! ) and if(!) for complex conditions.
Regarding the negation - You need to use De Morgan's laws for that negation. It essentially states:
NOT( A OR B ) <==> NOT(A) AND NOT(B)
NOT( A AND B ) <==> NOT(A) OR NOT(B)
NOT( ($odometer[$wheel] < 9 || $wheel < 0) )
NOT($odometer[$wheel] < 9 ) AND NOT ($wheel < 0)
$odometer[$wheel] >= 9 AND $wheel >= 0