If you mean the souvenir stalls at the foot of the church, they seem to be open all day. I do not know the exact opening/closing times.

Actually, the first time I went. It was going to rain and the hawker selling the antique Russian watches told me he's going home (in a Van). And the time was around 3 pm. Furthermore, he ain't going to open his store the next day with his own forecast of another rainny day. I think they close daily at around 5 pm when the nearby museums and cathedral are closing, too. They are also not open when it will be a rainny or snowy day. Those hawkers sell stuff/ souvenirs to foreigners who see "unusual" values in the merchandise "eg, Matryoshka dolls" they sell. So, good weather is a key factor la.

This week-end the church was closed. ( 21 april 2019)

Hello. In this time the market doesn`t work (( But anyway there is very nice place for making pictures. ))

ok

Hello Youri. I recommending you to make a search in Googl "individual tours in Kiev for foreigners", and you will get dozens addresses of excursion bureaus which professionally working with foreign tourists readily help you. The best wishes , Valery.