It’s trivial to find the number of syllables in Russian verses: you just count the number of vowel letters, and that’s it. Pushkin’s Eugene Onegin is available for download at Lib.ru. I manually extracted the verses from the text and adapted foreign words to Russian. Then I ran a simple command in Bash:

$ cat pushkin.txt | sed -e 's#[^аэыоуяеиёю]##gi' | awk '{print(length($1))}' | sort | uniq -c
     18 7
   2977 8
   2264 9

So there should be 5,259 verses in the poem, the vast majority with 8 or 9 syllables. The 7-syllable verses correspond to a song, Песня девушек, which is written in a different meter from the rest of the poem. As far as I could see, the remainder of the poem uses 14-verse stanzas, with six feminine endings and eight masculine endings in each stanza.

The ratio between masculine endings and feminine endings should therefore be 8/6 = 1.333, but in my case I obtained 1.315. There are many missing verses in the source text (indicated by a series of dots), which I didn’t count at all, so that could be the reason. That also at least partly explains why Wikipedia says there are 5,446 lines, but I found only 5,259. Maybe they counted the missing verses, or maybe they had a better source text.

There are many verses with foreign words, and even full verses written in French:

Reveillez vous, belle endormie.

Those were transcribed to Russian. I also wrote in full the names of letters, as in:

И русский Н как Н французский

The only time I cheated for real was with one verse:

Гм! гм! Читатель благородный,

This is the only verse I found for which the number of vowels does not correspond to the number of syllables.