As far as I understand it:
Relevant earnings would be your PAYE income and self-employed income (Case I/II or Case III if foreign trade/profession).
Where you have two sources of pensionable earnings and one relates to an occupational pension scheme, Revenue are of the view that for tax relief purposes the pension contributions must be paid in the first instance to the employer occupational scheme.
I presume that your declared nixer falls into Case I or II (profits from a trade/profession), and is not Case IV (miscellaneous income) which would not be relevant earnings for pension purposes.
If you had €90,000 PAYE income and €9,000 self-employed income and were in the 50-54 age range with the 30% allowable contribution, you could contribute and avail of full tax relief for a contribution of €27,000 to your employer's DC scheme (if applicable) and €2,700 to a PRSA.
If you had €115,000 of PAYE income (and kept all the other parameters above constant) you could contribute €34,500 to your employer's scheme. You could contribute to a PRSA from your self-employed earnings but could not avail of tax relief in the same tax year as you have hit the €115k earnings cap. You could claim tax relief in a future year depending on the circumstances.