The annual meeting of the council must take place on the day that councillors take office (this year on 9th May) or within 14 days thereof and councillors must sign their Declaration of Acceptance of Office at or before the first meeting (in practice that must be before in order for the meeting to be quorate) with the signature being in front of the clerk or another councillor. So, in the first instance, holding a meeting on the 9th, whilst legal for an uncontested election where papers can be served on known councillors, is quite early. For those who are not able to attend and/or do not attend, it is possible for the council to resolve to allow signature of a Declaration of Acceptance of Office at a later date, which is usually before the next council meeting. This suggests your council did not do that. There is nothing to stop you putting yourself forward for election (if a new election is triggered - check with your elections office) or for co-option.