I have been going out with a non-muslim for a year before he reverted to islam. We got engaged before his reversion and we are living together. We were due to get married a month after he became a muslim but he has been told by an imam to wait for 9 months now before we get married- is this permissible or is it better to get married quickly? I’m not sure please advise. Thank you.
If he has reverted to Islam truly and stared practicing so yes you can marry him whenever you want.
As far as waiting for 9 months is concerned so it is applicable in female case when she is pregnant. But in this case the revert muslim is male so you can marry him whenever you want.
But yes if you are pregnant so wait untl the delivery. And if you are pregnant by the above mentioned person so marry him as soon as possible and do a true Toba with wet eyes and as far as his Toba is concerned so he has done it since he accepted Islam and Islam removes all the sins happened in past so in this condition only you are left to do Toba.
~Allah knows better~