The "nine block" limit falls under the definition of a "Location". The O&G Act states that a location cannot contain more than 9 blocks. Then under Sec 37 in describing the PRL application process for someone with a PPL, it states:
(1) A licensee whose petroleum prospecting licence is in force in respect of the blocks that constitute a location may, within two years after the date on which the blocks were declared to be a location, or such further period as the Minister allows, make application to the Director for the grant of a petroleum retention licence in respect of such of the blocks as the licensee satisfies the Minister contain a gas field or a part of a gas field or, for the better administration of petroleum activities, should be included in a petroleum retention licence.
(2) A licensee may, during the term of a petroleum prospecting licence, make application to the Director for a petroleum retention licence in respect of any block or blocks within the licence area—
(a) that he satisfies the Minister contains or contain a gas field or part of a gas field, or, for the better administration of petroleum activities, should be included in a petroleum retention licence; and
(b) that do not at the time of making the application constitute a location."
So I believe they would not be limited to the 9 blocks per (2). It would be interesting to know which blocks make up those included in the "Location" granted to Tri/Bwata.