did i start it wrong or was it time to do it?

Hi Parents, I have 3 kids, (2 girls - 9 & 7 years old, 1 boy - 1.5 years old). I have always been that protective mum, obsessive mum & probably extra cautious to my girls. I have always remind them about taking care of themselves and not to mingle too much to boys, except in sch for sch matters but no boys communication after that. Last June, my older girl turns 9 and we thought after so much of observing, she seems to be very independant and someone whom we know is capable of any task. we bought her a mobile phone, those common Samsung model, not any high tech but she is able to communicate through whatsapp, watch youtube etc. All the phones account is under my name so that i could monitor what she watch etc exp of course her whatsapp chat. As a mum and seeing her growing up, i wanted to give her the feeling that this phone is given with trust. A trust that no boys should have her number and a trust that i should not check her phone unneccessarily. It is used as a form of communication between me and the kids at home coz we dont have a house phone. So my girl will update me about the other kids, we video call when i miss them at work, a sort of communication with the helper as well. She has always asked for my permission before using the phone and any friends (only girls allowed) needs her number will have to go through me. Means they will need to message me before i release her number. However, recently, my husband caught her using the phone was late at night. As a dad, he think no twice, and his intention to take the phone is to keep it away from her but to our disbelief, she has been messaging a boy from class with his name kept as "MY BFF". there were messages of "love you", "you wont leave me, right?" "are you mad at me?" etc. Emoticons of flying kisses, people kissing. she tried to defend herself by saying that all her bffs say I love you to each other. But what disturb me was that, she will iniate the message first and if no reply from the other user, she will keep messaging till he reply. she will message things like "are you angry at me?" "why you never reply me?' "what did i do wrong?' etc. sounds similar right to what adults would do to our other half. there was also 1 particular message that caught me when she asked " so is it you and me are boyfriend & girlfriend?' Understand from the chat history that she even left her girlfriends group because this boy doesnt like them or she told him to not friend with them because they hurt her something like that. Fyi, this boy is her classmates. i could not hold my anger and talk and reprimand her about her action and how she has broke my heart and my trust (not sure if its too early to make her understand about trust) We decide to confiscate her phone but i keep emphasizing her about her mistakes and that she lied behind me, she broke my rules and she hurts me. but after a few days, i am not sure if what i did was wrong at the start or is it the sign that i should have start my BGR talks with her. but she is only 9 years old. i dont know how to handle this. At a moment, she was like kind of mad at me for having to take away her phone, but i told her the reason of her actions. things were ok. but will she hate me? What would you do if you were in my shoe? and because of this, i am not able to video call the kids when i miss them or see their pictures when i miss them. but i know i cant give her the phone because my husband will definitely against it hard. but i just dont want my kids to hate me. What should i do?