Ok first we should be clear in our mind that 9 month Vaccination is given at - COMPLETED 9 MONTHS and not 9th running month. Hence as per history given by you, child should be completing 9 months on 30th April. That would be the due date for 9 month Vaccination I.e. MMR, OPV, Vit A, and Typhoid conjugate vaccine.
You can get it in first week of May. Or This vaccination can be delayed easily for 15 days to 1 month depending on lockdown scenario at that time
Next Steps
Stay home and rest reassured