The family rejected an offer of a mid 2020 graduation date from Eindhoven and claimed Laurent got less attention from the university after he revealed plans to split the next stage of his studies between the Netherlands and one of the many US universities competing for him to sign up to their courses.
"I don't understand how they can come suddenly to delay of six to eight months," Mr Simons, 37, said, "especially when he takes one exam a week. He has even taken three in one week in the past."
A copy of an email from Eindhoven university setting out the December exam schedule was posted on Laurent's Instagram account with the caption "liar, liar, pants on fire".
"The way they have acted is not correct a few weeks before he graduates. You can't imagine how disappointed Laurent is. He feels betrayed like any child would," Mr Simons said.
In a statement the university said it was impossible for Laurent, who lives in Amsterdam, to complete the course before turning ten while also developing "insight, creativity and critical analysis."
It warned rushing the course could harm Laurent's academic development and against putting "excessive pressure" on the nine-year-old, who had "unprecedented talent".
Mr Simons, a dentist, denied pressuring Laurent, who had less than ten exams to take, to leave the university or to continue his fast-tracked studies.
He said that Laurent socialises with children his own age on the weekend and will take part in swimming and karting clubs in the US. That was better than keeping a bored Laurent in school, where he was resented for being too fast and felt his fellow pupils were too slow, Mr Simons said.
Laurent now plans to take up an offer from one of the prestigious US universities who have been courting him. The exact university is being kept confidential by his parents at the institution's request.
He will move to the US with his grandparents and his parents will divide their time between Amsterdam and the States. Laurent speaks English and many of his courses in Eindhoven were taught in English.
Laurent is particularly excited at the prospect of being taught by the authors of the books used in his courses in the Netherlands, Mr Simons said.
He is confident Laurent will be able to complete his Bachelor's degree in the US before moving onto to even more advanced studies. He had considered studying at Oxbridge but was keen to go somewhere sunny.
The boy finished secondary school aged eight after completing six years of education in just a year and a half. His father and mother Lydia, 29, an office manager, watched him collect his diploma in a hall full of 18-year-olds.
